Type AT Signal - Alstom

Type AT Signal 

Copyright © 2008 Alstom Signaling Inc. 

Operation and Maintenance Manual 

P2502

Type AT Signal 

Copyright © 2008 Alstom Signaling Inc. 

Operation and Maintenance Manual 

Alstom Signaling Inc. 

P2502, Rev. February 2008, Printed in U.S.A.

LIST OF EFFECTIVE PAGES 

P2502, Type AT Signal Operation and Maintenance Manual 

ORIGINAL ISSUE DATE: April 2008 

CURRENT REVISION AND DATE: April 2008 

PAGE 

Cover 

Title page 

Preface 

i thru vi 

CHANGE OR REVISION LEVEL 

Apr/08 

Apr/08 

Apr/08 

Apr/08 

1–1 thru 1–8 Apr/08 

2–1 thru 2–8 Apr/08 

3–1 thru 3–4 Apr/08 

4–1 thru 4–8 Apr/08 

5–1 thru 5–4 Apr/08 

6–1 thru 6–12 Apr/08 

7–1 thru 7–42 Apr/08 

A–1 thru A–8 Apr/08 

P2502, Rev. Apr/08 Alstom Signaling Inc.

THIS PAGE INTENTIONALLY LEFT BLANK. 


PREFACE 

NOTICE OF CONFIDENTIAL INFORMATION 

Information contained herein is confidential and is the property of Alstom 

Signaling Incorporated. Where furnished with a proposal, the recipient 

shall use it solely to evaluate the proposal. Where furnished to customer, it 

shall be used solely for the purposes of inspection, installation or 

maintenance. Where furnished to a supplier, it shall be used solely in the 

performance of the contract. The information shall not be used or 

disclosed by the recipient for any other purposes whatsoever. 

FOR QUESTIONS AND INQUIRIES, CONTACT CUSTOMER SERVICE AT 

1–800–717–4477 

OR 

WWW.ALSTOMSIGNALINGSOLUTIONS.COM 

ALSTOM SIGNALING INC. 

1025 JOHN STREET 

WEST HENRIETTA, NY 14586 

REVISION LOG 

Revision Date Description By Checked Approved 

0 April 2008 Original issue MAS RR NI 




ABOUT THE MANUAL 

This manual is intended to provide the necessary information to maintain and ensure 

proper operation of the Type AT Signal. 

The information in this manual is arranged into sections. The title and a brief description 

of each section follow: 

Section 1 – GENERAL DESCRIPTION: This section gives general information on the 

components of the Type AT Signal. 

Section 2 – THEORY OF OPERATION: This section gives general information on the 

operation of the Type AT Signal. 

Section 3 – INSTALLATION: This section describes the field installation and setup of 

the Type AT Signal. 

Section 4 – PREVENTIVE MAINTENANCE: This section describes the tools, 

preventive maintenance procedures, and functional tests used on the Type AT Signal. 

The frequency and interval, for the performance of the given information, are also 

included. Safety precautions are also provided in this section. 

Section 5 – TROUBLESHOOTING: This section describes possible failures/symptoms 

along with the corrective action for the Type AT Signal. 

Section 6 – CORRECTIVE MAINTENANCE: This section describes the adjustment 

and replacement procedures associated with corrective maintenance of the Type AT 

Signal. Safety precautions are also provided in this section. 

Section 7 – PARTS CATALOG: This section identifies and lists the spare parts 

associated with operations of the Type AT Signal. 

Appendix A – DRAWINGS: This section has representative circuit drawings along with 

an installation and space requirement drawing of the Type AT Signal. 




MANUAL SPECIAL NOTATIONS 

In the Alstom manuals, there are three methods used to convey special informational 

notations to the reader. These notations are warnings, cautions, and notes. Both 

warnings and cautions are readily noticeable by boldface type two lines beneath the 

caption. 

Warning 

A warning is the most important notation to heed. A warning is used to tell the reader 

that special attention needs to be paid to the message because if the instructions or 

advice is not followed when working on the equipment then the result could be either 

serious harm or death. The sudden, unexpected operation of a switch machine, for 

example, or the technician contacting the third rail could lead to personal injury or death. 

An example of a typical warning notice follows: 

Caution 

WARNING 

WHENEVER THE GEAR COVER IS REMOVED DISCONNECT THE 

MOTOR ENERGY. OTHERWISE, THE SWITCH MACHINE MAY 

OPERATE UNEXPECTEDLY AND POSSIBLY CAUSE PERSONAL 

INJURY. 

A caution statement is used when an operating or maintenance procedure, practice, 

condition, or statement, which if not strictly adhered to, could result in damage to or 

destruction of equipment. A caution statement is also used when personnel could be 

surprised if shocked by a circuit operating at a low current. A typical caution found in a 

manual is as follows: 

Note 

CAUTION 

Turn power off before attempting to remove or insert circuit boards into a 

module. Boards can be damaged if power is not turned off. 

A note is normally used to provide minor additional information to the reader to explain 

the reason for a given step in a test procedure or to just provide a background detail. An 

example of the use of a note follows: 

NOTE 

A capacitor may be mounted on the circuit board with a RTV adhesive. 

Use the same color RTV. 




Topic 

TABLE OF CONTENTS 

Page 

1. SECTION 1 – INTRODUCTION............................................................................. 1–1 

1.1. SCOPE OF MANUAL ....................................................................................... 1–1 

1.2. GENERAL ........................................................................................................ 1–1 

1.3. PHYSICAL CHARACTERISTICS ..................................................................... 1–3 

1.3.1. Housing.......................................................................................................... 1–4 

1.3.2. Lens Assembly .............................................................................................. 1–5 

1.4. INCANDESCENT LIGHT SOURCE ................................................................. 1–6 

1.5. LED LIGHT SOURCE....................................................................................... 1–7 

2. SECTION 2– THEORY OF OPERATION.............................................................. 2–1 

2.1. GENERAL ........................................................................................................ 2–1 

2.2. FUNCTIONAL DESCRIPTION ......................................................................... 2–1 

2.3. TYPE AT INCANDESCENT SIGNAL FUNCTIONAL DESCRIPTION .............. 2–2 

2.3.1. Type AT Incandescent Signal Wiring............................................................. 2–3 

2.4. LED UNIT FUNCTIONAL DESCRIPTION........................................................ 2–4 

2.4.1. LED Lamp Wiring........................................................................................... 2–5 

3. SECTION 3 – INSTALLATION.............................................................................. 3–1 

3.1. GENERAL ........................................................................................................ 3–1 

3.2. SIGNAL MOUNTING........................................................................................ 3–1 

4. SECTION 4 – PREVENTIVE MAINTENANCE...................................................... 4–1 

4.1. GENERAL ........................................................................................................ 4–1 

4.2. PREVENTIVE MAINTENANCE........................................................................ 4–2 

4.2.1. Inspection ...................................................................................................... 4–3 

4.2.2. Lens Cleaning................................................................................................ 4–4 

4.2.3. Lubrication ..................................................................................................... 4–6 

4.2.4. Signal Operational Test ................................................................................. 4–7 

5. SECTION 5 – TROUBLESHOOTING.................................................................... 5–1 

5.1. GENERAL ........................................................................................................ 5–1 

5.2. TROUBLESHOOTING GUIDE ......................................................................... 5–1 

6. SECTION 6 – CORRECTIVE MAINTENANCE ..................................................... 6–1 

6.1. GENERAL ........................................................................................................ 6–1 

6.2. INCANDESCENT LAMP REPLACEMENT....................................................... 6–2 

6.3. LENS REPLACEMENT .................................................................................... 6–3 

6.4. TRANSFORMER REPLACEMENT .................................................................. 6–4 

6.5. LAMP RECEPTACLE REPLACEMENT ........................................................... 6–5 

6.6. LED MODULE REPLACEMENT ...................................................................... 6–6 

6.7. LED BOARD/ILLUMINATED NUMBER PLATE REPLACEMENT.................... 6–8 

6.8. SIGNAL HEAD REPLACEMENT...................................................................... 6–9 

6.9. WAYSIDE SIGNAL SITING............................................................................ 6–11 

P2502, Rev. Apr/08 i Alstom Signaling Inc.

Topic 

TABLE OF CONTENTS (CONT.) 

Page 

7. SECTION 7 – PARTS CATALOG ......................................................................... 7–1 

7.1. GENERAL ........................................................................................................ 7–1 

7.2. EXAMPLE SIGNALS ........................................................................................ 7–1 

7.3. LENSES ........................................................................................................... 7–3 

7.4. SINGLE ASPECT TYPE AT INCANDESCENT SIGNAL UNIT WITH 

TRANSFORMER.............................................................................................. 7–5 

7.5. 3 ASPECT TYPE AT INCANDESCENT SIGNAL, CEILING/HORIZONTAL 

MOUNT ............................................................................................................ 7–9 

7.6. 3 ASPECT TYPE AT INCANDESCENT SIGNAL, WALL MOUNT ................. 7–13 

7.7. 3 ASPECT TYPE AT INCANDESCENT SIGNAL, POLE MOUNT ................. 7–17 

7.8. LED UNITS..................................................................................................... 7–21 

7.9. 2 ASPECT TYPE AT SIGNAL UNIT WITH LED LIGHT SOURCE, 

POLE MOUNT................................................................................................ 7–23 


POLE MOUNT................................................................................................ 7–31 


CEILING/HORIZONTAL MOUNT ................................................................... 7–39 

A. APPENDIX A – DRAWINGS .................................................................................A–1 

A.1. GENERAL ........................................................................................................A–1 

A.2. TYPE AT INCANDESCENT SIGNAL WIRING DIAGRAMS.............................A–1 

A.3. TYPE AT SIGNAL UNIT WITH LED P/N 20179-0XX-00 WIRING DIAGRAMS A–4 

P2502, Rev. Apr/08 ii Alstom Signaling Inc.

Description 

LIST OF FIGURES 

Page 

Figure 1–1. Typical Three Aspect Type AT Signal ..................................................... 1–2 

Figure 1–2. Typical Three Aspect and Single Aspect Type AT Signal Housings, 

Side View .............................................................................................................. 1–4 

Figure 1–3. Typical Type AT Signal Active Light Compartment ................................. 1–5 

Figure 1–4. Typical Type AT Incandescent Signal ..................................................... 1–6 

Figure 1–5. Typical Type AT Signal LED Light Source Unit ....................................... 1–7 

Figure 2–1. Typical Type AT Incandescent Signal With Transformers 

Circuit Diagram...................................................................................................... 2–2 

Figure 2–2. Typical 3 Aspect Type AT Incandescent Signal With Transformers and 

Illuminated Number Plate Wiring........................................................................... 2–3 

Figure 2–3. Typical Type AT 3 Aspect LED Signal Wiring Diagram........................... 2–5 

Figure 2–4. Typical Type AT 3 Aspect LED Signal Wiring Diagram (Center Aspect 

is Blank) ................................................................................................................ 2–6 

Figure 2–5. Typical Type AT LED Single Aspect Signal Wiring Diagram................... 2–7 

Figure 3–1. Typical Wall Mount Type AT Signal ........................................................ 3–2 

Figure 3–2. Typical Ceiling (Horizontal) Mount Type AT Signal ................................. 3–3 

Figure 3–3. Typical 3 Aspect Pole Mount Type AT Signal ......................................... 3–4 

Figure 5–1. Incandescent Signal Aspect Dim or Not Illuminated................................ 5–2 

Figure 5–2. LED Signal Aspect Dim or Not Illuminated.............................................. 5–3 

Figure 5–3. LED or Illuminated Number Dim or Not Illuminated................................. 5–4 

Figure 7–1. Replacement Outer Lenses and Gaskets................................................ 7–3 

Figure 7–2. Example Single Aspect Type AT Incandescent Signal Unit With 

Transformer, AT007-000-00.................................................................................. 7–5 

Figure 7–3. Example 3 Aspect Type AT Incandescent Signal Unit Without 

Transformers, With Illuminated LED Number Plate, Ceiling/Horizontal Mount, 

AT000-108-00 ....................................................................................................... 7–9 

Figure 7–4. Example 3 Aspect Type AT Incandescent Signal Unit With 

Transformers, Enameled Number Plate, Door Stop and Side Plate, Wall Mount, 

AT000-001-00 ..................................................................................................... 7–13 

Figure 7–5. Example 3 Aspect Type AT Incandescent Signal Unit With 

Transformers, Enameled Number Plate, Door Stop and Side Plate, Pole Mount, 

AT000-024-00 ..................................................................................................... 7–17 

Figure 7–6. LED Unit P/N 20179-0XX-00................................................................. 7–21 

Figure 7–7. Example 2 Aspect Type AT Signal Unit With LED Light Source, 

Pole Mount, AT100-001-00 ................................................................................. 7–23 

Figure 7–8. Example 7 Aspect Type AT Signal Unit With LED Light Source, Pole 

Mount, AT100-002-00 ......................................................................................... 7–31 

Figure 7–9. Example 3 Aspect Type AT Signal Unit With LED Light Source, 

Ceiling/Horizontal Mount ..................................................................................... 7–39 

P2502, Rev. Apr/08 iii Alstom Signaling Inc.

Description 

LIST OF FIGURES (CONT.) 

Page 

Figure A–1. Typical Single Aspect Type AT Incandescent Signal Wiring Diagram ....A–1 

Figure A–2. Typical 3 Aspect Type AT Incandescent Signal Unit With Illuminated 

Number plate and Transformers Wiring Diagram..................................................A–2 

Figure A–3. Typical 4 Aspect Type AT Incandescent Signal Unit With Enameled 

Number Plate and Transformers Wiring Diagram (Single Aspect Plus 3 Aspect) .A–3 

Figure A–4. Typical Single Aspect Type AT Signal With LED Unit P/N 20179-0XX-00 

Wiring Diagram......................................................................................................A–4 

Figure A–5. Typical 3 Aspect Type AT Signal With LED Unit P/N 20179-0XX-00 Wiring 

Diagram.................................................................................................................A–5 

Figure A–6. Typical 3 Aspect Type AT Signal With LED Unit P/N 20179-0XX-00 and 

Illuminated Number Wiring Diagram......................................................................A–6 

Figure A–7. Typical Four Aspect Type AT Signal With LED Unit P/N 20179-0XX-00 

Wiring Diagram (Single Aspect Plus and 3 Aspect)...............................................A–7 

P2502, Rev. Apr/08 iv Alstom Signaling Inc.

Description 

LIST OF TABLES 

Page 

Table 1–1. Type AT Signal Basic Housing Dimensions .............................................. 1–5 

Table 4–1. Preventive Maintenance Index ................................................................. 4–2 

Table 4–2. Inspection Procedures.............................................................................. 4–3 

Table 4–3. External Lens Cleaning Procedure........................................................... 4–5 

Table 4–4. Lubrication Procedure .............................................................................. 4–6 

Table 4–5. Signal Operational Test Procedure .......................................................... 4–7 

Table 5–1. Troubleshooting Symbols......................................................................... 5–1 

Table 6–1. Corrective Maintenance Procedures ........................................................ 6–1 

Table 6–2. Incandescent Aspect Lamp Replacement Procedure............................... 6–2 

Table 6–3. Outer Lens Replacement Procedure ........................................................ 6–3 

Table 6–4. Signal Transformer Replacement Procedure ........................................... 6–4 

Table 6–5. Receptacle Replacement Procedure........................................................ 6–5 

Table 6–6. LED P/N 20179-0XX-XX Module Replacement Procedure ...................... 6–6 

Table 6–7. LED Board/Illuminated Number Plate Replacement Procedure ............... 6–8 

Table 6–8. Signal Head Replacement Procedure ...................................................... 6–9 

Table 6–9. Wayside Signal Siting Procedure ........................................................... 6–11 

Table 7–1. Replacement Outer Lenses...................................................................... 7–3 

Table 7–2. Example Single Aspect Type AT Incandescent Signal Unit With 

Transformer, AT007-000-02 Part Numbers........................................................... 7–7 

Table 7–3. Example 3 Aspect Type AT Incandescent Signal Unit Without 

Transformers, With Illuminated LED Number Plate, Ceiling/Horizontal Mount, 

AT000-108-01 Part Numbers .............................................................................. 7–11 

Table 7–4. Example 3 Aspect Type AT Incandescent Signal Unit With 



Table 7–5. Example 3 Aspect Type AT Incandescent Signal Unit With 



Table 7–6. LED Unit Part Numbers.......................................................................... 7–21 

Table 7–7. Example 2 Aspect Type AT Signal Unit With LED Light Source, Pole 

Mount, AT100-001-01 Part Numbers .................................................................. 7–27 

Table 7–8. Example 7 Aspect Type AT Signal Unit With LED Light Source, Pole 

Mount, AT100-002-01 Part Numbers .................................................................. 7–35 

Table 7–9. Example 3 Aspect Type AT Signal Unit With LED Light Source, 

Ceiling/Horizontal Mount Part Numbers .............................................................. 7–41 

P2502, Rev. Apr/08 v Alstom Signaling Inc.


P2502, Rev. Apr/08 vi Alstom Signaling Inc.

Introduction 

1. SECTION 1 – INTRODUCTION 

1.1. SCOPE OF MANUAL 

This manual is intended to provide the necessary information to maintain and ensure 

proper operation of the Type AT Signal. The technical material in this manual assumes 

the reader has a basic knowledge of railroad signaling terminology and basic 

maintenance principles. 

1.2. GENERAL 

This section briefly describes the components and physical characteristics of a typical 

Alstom Type AT transit signal, available with two types of light fixtures: 

• Incandescent Lamp P/N 48088-028-00 

• LED Unit P/N 20179-0XX-00 

The components and configuration of signals can vary depending on the specific 

requirements of their locations. Signals can be stacked to produce a multi Aspect signal. 

The signal can be wall, ceiling or pole mounted through the use of mounting brackets 

attached to the signal housing. Wall brackets hold a signal securely to a concrete wall or 

ceiling through the use of concrete bolts. A wall signal can be mounted in either a left or 

right hand configuration. These mounting configurations are produced by changing the 

position of the wall mounting bracket attached to the signal housing. Ladders can be 

provided where required. The Type AT Signal conforms to requirements of the AREMA 

Signal Manual, Part 7.1.1. 

P2502, Rev. Apr/08 1–1 Alstom Signaling Inc.

Introduction 

LENS 

ASSEMBLIES (3) 

HINGED 

BACK DOOR 

NUMBER PLATE ENAMEL 

OR ILLUMINATED 

3 ASPECT 

SIGNAL HOUSING 

Figure 1–1. Typical Three Aspect Type AT Signal 


Introduction 

1.3. PHYSICAL CHARACTERISTICS 

The Type AT Signal arrangement as well as the aspects and enamel number plate, vary 

depending on the location requirements. The configuration of the signal and use of 

illuminated or enamel number plate depends on the requirements of the location. Signal 

configurations are identified by the signal drawing number. Example configurations are 

shown and described within this manual. 

The Type AT 3 Aspect Signal, as shown in Figure 1–1, consists of a housing with 

hinged door, an illuminated or enamel number plate, three Aspect lens assemblies, and 

internal electrical components to illuminate the aspects and number plate if so 

configured. 

The Type AT Single Aspect Signal is often used in a multi Aspect application. The 

single aspect signal consists of a housing unit with a hinged door, a single aspect lens 

assembly, and internal electrical components to illuminate the aspect. 

This signal is available with the following options: 

• Mounting: 

− Wall Right Hand 

− Wall Left Hand 

− Column 

− Pole 

− Horizontal 

• Aspect Arrangements: 

− Red 

− Yellow 

− Lunar White 

− Timing indication (S) 

− Speed indication (15 or 20) 

− Blank (metal disk covers lamp compartment) 


Introduction 

1.3.1. Housing 

The signal housing is of cast-aluminum construction. Access to the internal parts of the 

signal is made through a hinged door at the rear of the housing. 

The Type AT 3 Aspect Signal is internally divided into four potentially active light 

compartments. Three compartments are used for aspect signals and one for the 

number display (number plate, illuminated (incandescent) number or LED number). The 

door of the three Aspect signal is equipped with two ventilators to prevent moisture and 

heat build-up within the housing and a gasket with sealant to prevent water from 

entering the housing. 

The Type AT Single Aspect Signal is available with or without an enamel number plate. 

The single aspect door has one ventilator. A latch is provided to padlock the door and 

prevent unauthorized access. 

Housings can be stacked to make 4, 5, 6, 7, or 8 aspect configurations. 

VENTILATORS 

4 COMPARTMENTS IN 

A 3 ASPECT SIGNAL 

NUMBER PLATE 

Figure 1-2. Typical Three Aspect and Single Aspect Type AT Signal Housings, 

Side View 


` 

Introduction 

Table 1–1. Type AT Signal Basic Housing Dimensions 

Dimension 3 Aspect Single Aspect 

Height 28.75" (73 cm) 9.75" (24.8 cm) 

Width 8.60" (21.8 cm) 8.60" (21.08 cm) 

Depth 9.69" (24.6 cm) 9.69" (24.6 cm) 

Outer Lens Diameter 5.0" (12.7 cm) 5.0" (12.7 cm) 

1.3.2. Lens Assembly 

The lens assembly of a Type AT Signal aspect, whether incandescent or LED, consists 

of a colored (Green, Yellow, or Red) lens and a mounting ring that holds the lens to the 

signal case. See Figure 1–3 for lens detail. 

LENS 

GASKETS 

LAMPS AND LAMP 

RECEPTACLES (2) 

LENS 

GASKETS 

LED LAMP UNIT 

TERMINAL POSTS 

BEZEL 

RING 

BEZEL 

RING 

LED UNIT 

OUTER 

LENS 

SCREW & 

WASHER 

GASKET 

LIGHTING 

TRANSFORMERS 

TERMINALS 

OUTER 

LENS 

SCREW & 

WASHER 

TYPE AT SINGLE ASPECT INCANDESCENT SIGNAL 

GASKET 

CENTERLINE OF 

OUTER LENS & 

LAMP UNIT LENS 

LED LAMP UNIT 

MOUNTING SCREW 

& WASHER 

TYPE AT SINGLE ASPECT LED SIGNAL 

Figure 1–3. Typical Type AT Signal Active Light Compartment 


Introduction 

1.4. INCANDESCENT LIGHT SOURCE 

Each active incandescent light source compartment uses two lamps. Each lamp has a 

single filament. 

An active aspect or illuminated number plate light compartment contains a lighting 

transformer, terminals for power connection, and appropriate lamp receptacles as 

shown in Figure 1–4. 

LIGHTING 

TRANSFORMERS (2) 

ASPECT 

LENS 

ASSEMBLY 

LAMPS AND 

LAMP RECEPTACLES (2) 

TERMINALS 



TERMINALS 

FRONT VIEW 

ILLUMINATED 


SIDE VIEW 

LIGHTING 

TRANSFORMERS (2) 

Figure 1-4. Typical Type AT Incandescent Signal 


Introduction 

1.5. LED LIGHT SOURCE 

The LED light source unit P/N 20179-0XX-00 measures 2.2” (5.6 cm) in diameter. It is a 

self contained unit; the lens and individual LEDs are not replaceable. 

Two secured color coded 300V, 125ºC, 16 AWG jacketed wires 12" (30.5 cm) long with 

ring terminals compatible with the AAR terminal posts (.242” O.D. [.61 cm]) are 

provided. The AAR terminal posts are provided for field electrical connections. 

Figure 1-5. Typical Type AT Signal LED Light Source Unit 

The LED lamp units used on this project have the following physical characteristics: 

• Color • Light Angle 

− Red 

− 20 degree 

− Green • Operating Voltage 

− Yellow 

− 110 VAC (60Hz) 

− Lunar White • Brightness 

• BackLight − Fixed, Not Adjustable 


Introduction 

. 



Theory of Operation 

2. SECTION 2– THEORY OF OPERATION 

2.1. GENERAL 

This section contains operating information on the Alstom Type AT Signal along with 

diagrams showing power distribution and wiring to the signal. 

2.2. FUNCTIONAL DESCRIPTION 

Type AT Signals are controlled externally through relay logic circuits or vital processors. 

Depending on the distance of the signal from the relay room, power supplied to the 

signal may vary. 



2.3. TYPE AT INCANDESCENT SIGNAL FUNCTIONAL DESCRIPTION 

Type AT Incandescent Signals are configured with transformers to operate on fused 60 

Hz (ungrounded), 110 VAC power, controlled externally through relay logic circuits. 

Depending on the distance of the signal from the power source, the nominal 110 VAC 

power supplied to the primary windings of the signal transformers may vary. It must, 

however, be between 90 to 130 VAC (60 Hz) for the signal to function properly. 

Figure 2–1 is a simplified circuit diagram of a Type AT 3 Aspect Signal with 

transformers. One aspect contains two single filament lamps installed in a receptacle 

assembly consisting of two non-tapping transformers, two lamp receptacles, and a 

terminal block attached to a mounting bracket. 

Terminal connection points A, C, and E from terminal blocks within the three signal 

aspects, are connected to the signal lighting relay logic circuits. These circuits receive 

power through a fused feed, from an energy source in the relay room. The three 

aspects, points A, C, and E, are fed from a single fuse. The common 1 and 2 feeds 

(points B and F) are not fused. These feeds are connected to the same energy source 

but not through the relay logic control circuits. A signal lamp receives the 10 VAC from a 

transformer within the signal. Detailed wiring diagrams on specific Type AT Signals are 

given in Appendix A. 

LAMP 

TERMINAL CONNECTION POINTS 

TRANSFORMER A TRANSFORMER 

LAMP 

10 

VAC 

110 

VAC 

110 

VAC 

10 

VAC 

ASPECT 1 

B 

C 

10 

VAC 

110 

VAC 

110 

VAC 

10 

VAC 

ASPECT 2 

D 

E 

10 

VAC 

110 

VAC 

110 

VAC 

10 

VAC 

ASPECT 3 

F 

Figure 2–1. Typical Type AT Incandescent Signal With Transformers Circuit Diagram 



2.3.1. Type AT Incandescent Signal Wiring 

Figure 2–2 is a wiring diagram of a typical Type AT Incandescent 3 Aspect Signal with 

transformers. The signal wiring shown in dotted lines represents the field wiring of a 

seven conductor, number 14 AWG cable. The internal wiring of lamps and transformers 

are represented by solid lines. 

G 

Y 

R 


NO. PLATE 

110 VAC 

COMMON (BCX OR ACX) 

LAMPS 

TRANSFORMERS 

TERMINAL 

BLOCK 

BLACK 

BCX 

ILLUM 


R Y ACX G 

RED 

TYPICAL WIRING OF A 

LAMP AND TRANSFORMER 

Figure 2–2. Typical 3 Aspect Type AT Incandescent Signal With Transformers and 

Illuminated Number Plate Wiring 



2.4. LED UNIT FUNCTIONAL DESCRIPTION 

The LED Unit P/N 20179-0XX-00 is available in 4 colors: 

• Green LED 20179-008-00 

• Red LED 20179-009-00 

• Yellow LED 20179-010-00 

• Lunar White LED 20179-011-00 

This is a single, self-contained device that does not require any field assembly. The 

lamp is wired via ring terminals to AAR terminal posts within the signal unit. 

Each unit contains an LED board and a power supply board contained in the signal 

housing. These housings are replaceable as a unit and are not serviceable. 

The LED unit power boards operate from 90 to 130 VAC (60 Hz. 



2.4.1. LED Lamp Wiring 

Figure 2–3 is a wiring diagram of a typical three aspect LED Unit P/N 20179-0XX-00 

LED signal configured, green, yellow, and red. 

The signal wiring shown in dotted lines represents field wiring of multi-conductor 

number 14 AWG cable. Signal number is represented by xxx in this example. See 

Appendix A for additional example wiring diagrams. 

G 

1 

2 

Y 

1 

2 

R 

1 

2 

xxxRG 

xxxHG 

ACX 

xxxDG 

Figure 2-3. Typical Type AT 3 Aspect LED Signal Wiring Diagram 



Figure 2–4 is a wiring diagram of a typical three aspect LED signal (one aspect blank) 

configured red, blank, red. 

The signal wiring shown in dotted lines represent field wiring of four-conductor number 

14 AWG cable. 

R 

1 

2 

X 

R 

1 

2 

ACX 

xxxRG 

Figure 2-4. Typical Type AT 3 Aspect LED Signal Wiring Diagram 

(Center Aspect is Blank) 



Figure 2–5 is a wiring diagram of a typical one aspect LED signal. 

The signal wiring shown in dotted lines represent field wiring of two-conductor number 

14 AWG cable. 

L 

1 

2 

CX 

L 

Figure 2-5. Typical Type AT LED Single Aspect Signal Wiring Diagram 



. 



Installation 

3. SECTION 3 – INSTALLATION 

3.1. GENERAL 

This section describes installation of the Alstom Type AT Signal. If a fault is suspected 

upon installation, the maintainer should refer to Section 5 for the proper signal 

troubleshooting procedure. 

3.2. SIGNAL MOUNTING 

The Type AT Signal can be mounted on a wall, ceiling (horizontal) or pole. The wall and 

ceiling mounted signals are mounted using brackets. The pole mounted signal is 

mounted on a 3” (7.62 cm) diameter pole. The pole is inserted in and fastened to a cast 

aluminum split base. The split base is bolted to a concrete foundation. Example 

mounting configurations are shown in Figures 3-1 through 3-3. 

Refer to Section 7 for example parts and signal assembly drawings. To determine the 

part number to use when ordering a complete signal for your configuration or to obtain 

the parts list for your specific configuration, contact your Alstom Signaling Inc. 

representative. 


Installation 

Figure 3-1. Typical Wall Mount Type AT Signal 


Installation 

Figure 3-2. Typical Ceiling (Horizontal) Mount Type AT Signal 


Installation 

Figure 3–3. Typical 3 Aspect Pole Mount Type AT Signal 


Preventive Maintenance 

4. SECTION 4 – PREVENTIVE MAINTENANCE 

4.1. GENERAL 

This section describes preventive maintenance and testing for the Alstom Type AT 

Signals. If a fault is suspected as a result of this maintenance, the maintainer should 

refer to Section 5 for the proper signal troubleshooting procedure. 

Preventive maintenance procedures deal with inspection, cleaning, and preventive 

maintenance (PM) checks. PM checks are performed to ensure proper equipment 

operation based on specific tolerances. These checks identify and isolate possible 

malfunctions. 

Corrective maintenance, at the field service level, is intended to restore malfunctioning 

equipment to its normal operating condition as quickly as possible. Corrective 

maintenance procedures including component replacement, voltage adjustments, and 

wayside sighting are provided in Section 6. 



4.2. PREVENTIVE MAINTENANCE 

Table 4–1 lists the typical preventive maintenance procedures for the Type AT Signal. 

The Interval column gives the recommended frequency of procedures. The 

Maintenance Action column lists the preventive maintenance procedure to be performed 

at the prescribed interval. The Reference column lists the table number containing the 

procedure. 

Table 4–1. Preventive Maintenance Index 

Interval Maintenance Action Reference 

Monthly Periodic Inspection Table 4–2 

Monthly External Lens Cleaning Table 4–3 

Quarterly Door Handle, Hinge and Latch Lubrication Table 4–4 

As Needed Signal Operational Test Table 4–5 

WARNING 

ABIDE BY ALL OPERATIONAL AND SAFETY RULES WHEN 

ENTERING AND WORKING IN THE RIGHT OF WAY. 



4.2.1. Inspection 

The Inspection Procedure can be performed any time personnel are in close proximity 

to the signal. Follow the inspection procedures as outlined in Table 4–2, in the order 

given. If required, take the corrective actions described to be sure the signal is properly 

serviced. 

Table 4–2. Inspection Procedures 

Step Procedure Action 

1 Inspect cases for scratches, large dents, 

cracks, warped doors, or other obvious 

mechanical damage. 

2 Check for loose hardware or loose 

connections. 

3 Inspect interior of signal housing for 

excessive dirt, dust, or foreign objects. 

4 Inspect wiring and cables for broken or brittle 

wires or cracked insulation. 

5 Verify each lamp illuminates when energized 

and check for proper brightness 

Paint scratches and replace 

excessively damaged parts. 

Tighten. 

Remove foreign objects. Clean 

case with damp lint-free cloth. 

Clean lens. 

Replace wire or cable. 

Refer to Troubleshooting 

Section 5. 

6 Inspect for excessive dirt or dust on lens Clean external lens; see Table 

4–3. 

7 Inspect for cracked or broken external lens. Replace lens, as required, see 

corrective maintenance, Table 

6–3. 

8 Inspect vent screen in door for air blockage. Clean screen with brush. 

9 Inspect door handle, hinges and latch. Lubricate as required, see Table 

4–4. 

10 Inspect grounding of signal. (When 

Applicable) 

Clean and tighten connections. 

11 Inspect condition of door gasket(s) (1 per 

door). 

Replace damaged gasket. 



4.2.2. Lens Cleaning 

Clean lenses any time an inspection reveals the need for cleaning. 

CAUTION 

Do not look directly into an illuminated lamp at close range. 

Tools required for lens cleaning include: 

• Cleaners such as Brillianize (The Brillianize Company), Novus Plastic Polish No. 1 

(Novus Plastic Polish Ltd.) or equivalent plastic cleaner and polish approved for use 

on polycarbonate and Plexiglas® lenses 

NOTE 

If no other cleaner is available, use a solution of one part mild dishwashing 

liquid to 50 parts water. Rinse each lens with clean water and dry 

immediately with a damp chamois. 

• Pump or spray dispenser 

• Damp chamois 

CAUTION 

Never use an abrasive to clean a lens. 

Do not use a dry chamois on a dry lens; this prevents accidental 

scratching of the lens. Do not use a cleaner with ammonia; this type of 

cleaner may attack the lens material. 



Table 4–3. External Lens Cleaning Procedure 

Step 

Procedure 

1 WARNING 

Spray lens. 

USE A SAFETY BELT WHEN THE CLEANING LENSES OF ANY 

POLE MOUNTED UNIT WHILE STANDING ON LADDER STEPS. 

WARNING 

DO NOT LOOK DIRECTLY INTO AN ILLUMINATED LAMP AT 

CLOSE RANGE. 

2 Wipe lens with a damp chamois. 



4.2.3. Lubrication 

Hinges on doors, door handles, and padlocks are lubricated with lightweight mineral 

based oil (Mobil Aero HFA or equivalent). 

Table 4–4. Lubrication Procedure 

Step 

Action 

1 Sparingly oil door hinges, locking eyebolt, and any padlocks used. 

LUBRICATE 

LUBRICATE 

2 Wipe off excess oil. 



4.2.4. Signal Operational Test 

The Signal Operational Test verifies the visibility of the signal. If an indication is not met, 

proceed to Troubleshooting, Section 5. This operational test that should be performed 

when: 

• a signal malfunction is suspected 

• the signal or one of its components has been repaired 

• the signal or one of its components has been replaced 

WARNING 

DO NOT LOOK DIRECTLY INTO AN ILLUMINATED LAMP AT CLOSE 

RANGE. 

Table 4–5. Signal Operational Test Procedure 

Step 

Action 

1 Call each signal aspect and verify the correct LED module is lit. 

2 From a position 300 feet in approach to the signal and six feet over the top 

of the running rail, view signal at stop. Aspect must be clearly visible. 

3 If any viewed signal aspect is dim or not illuminated refer to Section 5 for 

Type AT Signal troubleshooting. 





Troubleshooting 

5. SECTION 5 – TROUBLESHOOTING 

5.1. GENERAL 

Troubleshooting information is given in the form of a fault isolation flowchart provided in 

Figure 5–1. The chart begins with the malfunction symptoms and, based on 

observations and tests by the maintainer, the chart branches out to isolate probable 

causes of the malfunction. 

Troubleshooting flowchart symbols are explained in Table 5–1. 

5.2. TROUBLESHOOTING GUIDE 

The guide gives instructions on how to sequentially do a series of checks or tests, 

resulting in a practical repair solution. It is important to follow the instructions in the 

sequence given. 

Table 5–1. Troubleshooting Symbols 

Symbol 

Explanation 

Malfunction statement as derived from operator's report. 

Basic instruction for preparation of a test, procedure, or 

observation. The action taken results in a diagnostic 

decision. 

Result from previous action, which is answered yes or no. If 

result is within tolerance, answer yes. If not, answer no. Do 

not consider any gray areas between yes and no. 

Final step of instructions involving corrective measures. 

Reference publication indicates suspected problem area. 



SIGNAL ASPECT 

DIM OR NOT ILLUMINATED 

CHECK CONDITION OF 


RECEPTACLES 

(SEE NOTE 1) 

YES 

OK? 

NO 

CHECK FOR 110 VAC 

AT SIGNAL LIGHTING 

TRANSFORMER 

PRIMARY 

(SEE NOTE 2) 

REPLACE 

LAMPS AND/OR 

RECEPTACLES 

YES 

OK? 

NO 



TRANSFORMER 

SECONDARY 

(SEE NOTE 3) 

CHECK 

CONDITION 

OF POWER 

FEED FUSES 

YES 

OK? 

NO 

YES 

OK? 

NO 


AT ASPECT 

RECEPTACLES AND 

TERMINAL BLOCK 

(SEE NOTE 3) 

REPLACE 

TRANSFORMER 

TROUBLESHOOT 

110 VAC POWER 

SUPPLY AND 

FIELD WIRING 

REPLACE 

FUSES 

YES 

OK? 

NO 

NOTES: 

1. FOR A THREE ASPECT SIGNAL, DETERMINE 

WHETHER SIGNAL IS CONDITIONED TO CLEAR OR TO 

STOP BEFORE CHECKING LAMP CONDITION. 

REPLACE 

LAMP AND 

CLEAN LENS 

REPLACE/REPAIR 

LAMP WIRING AS 

REQUIRED 

2. FOR A THREE ASPECT SIGNAL WITHOUT AN 

INTERNAL SIGNAL LIGHTING TRANSFORMER, CHECK 

SIGNAL LIGHTING TRANSFORMER IN CASE. 

3. FOR SIGNALS WITHOUT AN INTERNAL 

TRANSFORMER, THE OUTPUT VOLTAGE AT SIGNAL 

LIGHTING TRANSFORMER SECONDARY MAY BE 

HIGHER THAN 10 VAC TO COMPENSATE FOR 

DISTANCE BETWEEN SIGNAL AND TRANSFORMER. 

Figure 5–1. Incandescent Signal Aspect Dim or Not Illuminated 



SIGNAL ASPECT 


CHECK CONDITION OF LED 

LAMP UNIT RING TERMINAL 

CONNECTION TO THE 

LED SIGNAL TERMINAL 

NOTE: 

1. DETERMINE THE SIGNAL 

CONTROL CONDITION BEFORE 

CHECKING LED INTEGRITY. 

YES 

OK? 

NO 

CHECK FOR CORRECT 

VOLTAGE AT LED 


TIGHTEN 

CONNECTION OR 

REPLACE TERMINALS 

AS NEEDED 

YES 

OK? 

NO 

REPLACE 

LED MODULE 

CHECK 

CONDITION 

OF POWER 

FEED FUSES 

YES 

OK? 

NO 

REPLACE 

FUSES 

CHECK FOR 

CORRECT VOLTAGE AT 

SIGNAL LIGHTING 

POWER SUPPLY 

IN RELAY ROOM 

YES 

OK? 

NO 

TROUBLESHOOT 

AND REPAIR 

FIELD WIRING 

TROUBLESHOOT 

POWER 

DISTRIBUTION 

Figure 5-2. LED Signal Aspect Dim or Not Illuminated 



SIGNAL ASPECT 


CHECK CONDITION OF LED 

LAMP UNIT RING TERMINAL 

CONNECTION TO THE 

LED SIGNAL TERMINAL 

NOTE: 

1. DETERMINE THE SIGNAL 

CONTROL CONDITION BEFORE 

CHECKING LED INTEGRITY. 

YES 

OK? 

NO 

CHECK FOR CORRECT 

VOLTAGE AT LED 


TIGHTEN 

CONNECTION OR 

REPLACE 

TERMINALS AS 

NEEDED 

YES 

OK? 

NO 

REPLACE LED 

BOARD/ 



CHECK 

CONDITION 

OF POWER 

FEED FUSES 

YES 

OK? 

NO 

REPLACE 

FUSES 

CHECK FOR 

CORRECT VOLTAGE 


POWER SUPPLY 

IN RELAY ROOM 

YES 

OK? 

NO 

TROUBLESHOOT 

AND REPAIR 

FIELD WIRING 

TROUBLESHOOT 

POWER 

DISTRIBUTION 

Figure 5–3. LED or Illuminated Number Dim or Not Illuminated 


Corrective Maintenance 

6. SECTION 6 – CORRECTIVE MAINTENANCE 

6.1. GENERAL 

Corrective maintenance, at the field level, is intended to restore proper operation to 

malfunctioning equipment by replacing components found to be faulty through the 

troubleshooting procedures described in Section 5 and the preventive maintenance 

procedures described in Section 4. 

This section contains procedures for replacing the Type AT Signal lamps, transformers, 

receptacles, LED modules and lenses used in the various light source versions of the 

signals as well as signal head replacement and wayside signal siting procedures, as 

listed in Table 6–1. 

Table 6–1. Corrective Maintenance Procedures 

Interval Maintenance Action Reference 

Periodically, as 

determined by local 

authorities 

Incandescent Lamp Replacement Table 6–2 

As Needed Outer Lens Replacement Table 6–3 

As Needed Transformer Replacement (If used) Table 6–4 

As Needed 

As Needed or every 

43,800 hours 

Lamp Receptacle Replacement 

(For Incandescent Versions of the AT Signal Only) 

Table 6–5 

LED Unit P/N 20179-0XX-XX Replacement Table 6–6 

As Needed LED Board/Illuminated Number Plate Replacement Table 6–7 

As Needed Signal Head Replacement Table 6–8 

As Needed Wayside Signal Siting Table 6–9 

WARNING 

VERIFY THAT POWER IS REMOVED FROM THE SIGNAL UNIT PRIOR 

TO PERFORMING ANY CORRECTIVE MAINTENANCE PROCEDURE. 

WARNING 

ABIDE BY ALL OPERATIONAL AND SAFETY RULES WHEN 

ENTERING AND WORKING IN THE RIGHT OF WAY. 



CAUTION 

Do not look directly into an illuminated light source at close range. 

CAUTION 

Allow incandescent lamps to cool before touching them. 

6.2. INCANDESCENT LAMP REPLACEMENT 

Incandescent lamps should not be allowed to burn themselves out. Replace aspect 

lamps according to the Authority's schedule, using the procedure listed in Table 6–2. 

Table 6–2. Incandescent Aspect Lamp Replacement Procedure 

Step 

Procedure 

1 Remove power to signal by removing power feed fuses. (Refer to circuit 

drawings for location and identity of power feed fuses.) 

2 Remove padlock and open rear door. 

3 Press lamp into socket and turn counter-clockwise. Remove lamp from socket 

and discard. Repeat for second lamp. 

4 Align bayonet pins on replacement lamp with slots in socket. Push lamp into 

socket. Turn lamp 1/4 turn clockwise. Release lamp. Repeat for second lamp. 

5 Repeat steps 3 and 4 for additional light compartments. 

6 Reapply power to the signal by reinstalling the power feed fuses. 

7 Verify lamp operation per Signal Operational Test, Table 4–5. 

8 Close rear door. Re-install and lock padlock. 


` 


6.3. LENS REPLACEMENT 

Replace an aspect light lens using the procedure listed in Table 6–3 in the sequence 

given. There is no need to re-focus the signal after a lens is replaced. Refer to the 

exploded view of a lens assembly shown in Section 6. 

There is no need to refocus the signal after a lens is replaced. 

Table 6–3. Outer Lens Replacement Procedure 

Step 

Procedure 

1 Remove power to signal by removing power feed fuses. (Refer to circuit 



3 Remove four screws securing lens assembly to signal case. Lens and lens ring 

are released. 

LENS 

GASKETS 



LENS 

GASKETS 

LED LAMP UNIT 


BEZEL 

RING 

BEZEL 

RING 

LED UNIT 

OUTER 

LENS 

SCREW & 

WASHER 

GASKET 

LIGHTING 

TRANSFORMERS 

TERMINALS 

OUTER 

LENS 

SCREW & 

WASHER 

TYPE AT SINGLE ASPECT INCANDESCENT SIGNAL 

GASKET 

CENTERLINE OF 

OUTER LENS & 


LED LAMP UNIT 


& WASHER 

TYPE AT SINGLE ASPECT LED SIGNAL 



Table 6–3. Outer Lens Replacement Procedure (Cont.) 

Step 

Procedure 

4 Remove the bezel ring, gaskets and outer lens from the housing. 

5 Remove the outer lens and replace outer lens gasket. 

6 Replace outer lens, verifying that the outer lens gasket is uniformly in place 

against the signal case. Replace gaskets if they are not in good condition. 

7 Reinstall the bezel ring, gaskets and outer lens from the housing. 

8 Tighten the 4 screws holding bezel ring, gaskets and outer lens to the housing. 



11 Close rear door. Reinstall and lock padlock. 

6.4. TRANSFORMER REPLACEMENT 

Replace signal transformer using the procedure listed in Table 6–4 in the sequence 

given. 

Table 6–4. Signal Transformer Replacement Procedure 

Step 

Procedure 

1 Remove power to signal head by removing power feed fuses. (Refer to circuit 



3 Identify, tag, and disconnect wires of transformer. 

4 Remove the two screws securing transformer to receptacle bracket and remove 

transformer. 

5 Install new transformer and reconnect wires as tagged. 






6.5. LAMP RECEPTACLE REPLACEMENT 

A lamp receptacle can be replaced using the procedure listed in Table 6–5, as long as 

the mounting bracket is not moved or replaced. Moving or replacing the mounting 

bracket effects the horizontal and vertical position of the lamp, as well as lamp distance 

from the lens. The lamp position controls the illuminating quality of an aspect. 

Should an aspect lamp receptacle be defective and warrant replacement, then the 

entire receptacle unit should be removed and replaced. Since the horizontal and vertical 

position of the lamp receptacle, as well as the distance of the lamp receptacle distance 

from the lens, controls the illuminating quality of an aspect, care should be taken to 

position the new receptacle unit in the same position as the replaced unit. 

The illuminating quality of an aspect is changed through horizontal and vertical position 

adjustments made to the signal head lamp receptacle unit while viewing the aspect 

approach from a distance of up to 300 feet and about 6 feet above the running rail. A 

formal test specification (Alstom specification number ATS-10Q-28) exists for shop use. 

This specification may be used in field locations. 

Table 6–5. Receptacle Replacement Procedure 

Step 

Procedure 

1 Remove power to signal head by removing power feed fuses. (Refer to circuit 



3 Identify, tag, and disconnect wires from the lamp receptacle. 

4 Remove lamp from receptacle and screws securing receptacle to the receptacle 

bracket. 

5 Remove receptacle and install new receptacle. 

6 Reconnect wires as tagged on new lamp receptacle. 






6.6. LED MODULE REPLACEMENT 

LED P/N 20179-0XX-XX modules should be replaced before the end of their life 

expectancy. Replace LED modules as determined by the local authorities. LED module 

life is approximately 43,800 hours. Use the procedure provided in Table 6–6 to replace 

the LED module. 

Table 6–6. LED P/N 20179-0XX-XX Module Replacement Procedure 

Step 

Action 

1 Remove power to the signal by removing its power feed fuses. (Refer to circuit 

drawings for location of power feed fuses.) 


3 Verify that field wires connected to the signal head are tagged or tag, as 

necessary. 

4 Disconnect the field wiring from the LED Signal Terminal Posts. 

LED LAMP UNIT 

AAR TERMINAL POSTS 

LENS 

GASKETS 

BEZEL 

RING 

LED 

LAMP 

UNIT 

C L 

OUTER 

LENS 

SCREW & 

WASHER 

GASKET 

CENTERLINE OF 

OUTER LENS & 


LED LAMP UNIT 


& WASHER 



Table 6–6. AT LED Unit P/N 20179-0XX-XX Replacement Procedure (Cont.) 

Step 

Action 

5 Remove the fasteners holding the LED lamp unit to the housing mounting 

brackets. 

6 Remove the LED lamp unit. 

7 Remove retaining fasteners and standoffs from old LED lamp unit mounting 

bracket. 

8 Install retaining fasteners and standoffs onto new LED lamp unit mounting 

bracket. 

NOTE 

Use the same mounting holes in the new LED lamp unit mounting 

bracket as were used in the old unit to ensure the unit can be 

mounted and aligned properly. 

9 Place the new LED lamp unit into position. 

10 Tighten the fasteners holding the LED lamp unit to the housing brackets. 

11 Reconnect the field wires to the LED lamp unit AAR terminal posts. 

12 Repeat steps 3 through 11 for any additional LED lamp units requiring 

replacement. 






6.7. LED BOARD/ILLUMINATED NUMBER PLATE REPLACEMENT 

Replace the LED board/illuminated number plate unit using the procedure listed in 

Table 6–7 in the sequence given. 

Table 6–7. LED Board/Illuminated Number Plate Replacement Procedure 

Step 

Action 

1 Remove power to the signal by removing its power feed fuses. (Refer to circuit 

drawings for location of power feed fuses.) 


3 Identify and disconnect LED board wires from terminal in signal head housing. 

4 Remove the four screws securing the LED board/illuminated number plate to the 

signal housing. 

5 Install the new LED board/illuminated number plate to the signal housing. 

6 Reconnect LED board wires to terminal in signal head housing. 

7 Apply power to signal by replacing power feed fuses. 

8 Perform Signal Operational Test, Table 4–5. 




6.8. SIGNAL HEAD REPLACEMENT 

The signal head replacement procedure provided in Table 6–8 applies to the pole, wall, 

and ceiling mounted signal examples provided in this manual. Your installation may 

vary. 

CAUTION 

Signal heads are heavy. Stand clear of falling signal heads or obtain help 

to hold the signal head during removal so that it does not fall on you. The 

use of a rope and pulley or a come-along is recommended to raise and 

lower the signal. 

Table 6–8. Signal Head Replacement Procedure 

Step 

Procedure 

1 Remove the power to the signal head by removing the power feed fuses. (Refer 

to the circuit drawings for location and identity of the power feed fuses in the 

relay room.) 

2 Remove the padlock and open rear door. 

3A Pole mounted signal head removal: 

Identify, tag, and disconnect the wires contained in the signal head that connect 

to wires in the pole. Loosen the bolts on the signal head mounting socket and lift 

the signal head off. 



Table 6–8. Signal Head Replacement Procedure (Cont.) 

Step 

3B 

Procedure 

Wall or ceiling mounted signal head removal: 

Disconnect the conduit; verify that wires connected to the signal head are 

tagged or tag, as necessary. Disconnect wires. 

Remove the bottom two bolts that secure the signal head to the wall; then 

remove the top two bolts, and lower the signal head to the ground, using caution 

to remain clear of the lowered equipment. Let the cable come out of the signal 

head. 

4 If signal is equipped with an enamel number plate, detach plate from the 

removed signal head and secure it to the replacement signal head. Replace 

number plate gaskets as needed. 

5 Secure the replacement signal head to the mounting by reversing the procedure 

used to remove the replaced signal head, as follows: 

Pole mounted: Feed the cable through the replacement signal head. Lower the 

signal head onto the pole and tighten the bolts on the signal head mounting 

socket. Reconnect the wires tagged in Step 3A. 

Wall mounted: Feed the cable through the replacement signal head. Raise the 

signal head into position and secure to the wall using the four bolts removed in 

Step 3. Replace the conduit. Reconnect the wires tagged in Step 3B. 



8 Complete the Wayside Signal Siting provided in Table 6–9. 




6.9. WAYSIDE SIGNAL SITING 

After installing a new signal head, the procedure in Table 6–9 is to be performed to 

ensure that the oncoming train operator properly sees the signal. 

Table 6–9. Wayside Signal Siting Procedure 

Step 

Procedure 

1 Sight the signal head starting from a position 300 ft (91.44 m) in approach to the 

signal and 6 ft (1.83 m) over the top of the running rail (use the running rail 

located beneath the train operator). Sight the signal at 30 ft (9.14 m) intervals 

moving towards the signal. 

Where the track in approach to the signal is not tangent, sight the signal 

throughout a 150 ft (45.72 m) approach distance. 

Record the sighting distance used on the data sheet for future reference. 

2 Verify that the signal is properly aligned for optimum visibility of the illuminated 

signal aspect throughout the 300 ft (91.44 m) approach distance. 

3 Verify that the illuminated signal aspect is continuously readily readable 

(distinguishable from the non-illuminated signal heads without glare) throughout 

the 300 ft (91.44 m) approach distance. 

4 Verify that there is an unobstructed (clear) view of the illuminated signal aspect 

throughout the 300 ft (91.44 m) approach distance. 

5 Perform steps 1 through 4 for each signal aspect in the signal under test. 

6 Repeat this procedure for each signal in the location under test. 

Should an aspect appear to dim when viewing the aspect on the approach from a 

distance of up to 300 ft (91.44 m) and about 6 ft (1.83 m) above the running rail, follow 

the troubleshooting procedure(s) in Section 5. 






7. SECTION 7 – PARTS CATALOG 

7.1. GENERAL 

This section describes and shows the main component replacement parts for example 

Type AT Signals. 

Replacement parts shown are the lowest level replaceable unit (LLRU) that can be 

ordered. The LLRU is a component part that can be easily removed and replaced 

without using special tools or equipment. 

7.2. EXAMPLE SIGNALS 

The basic signal cases include single aspect and three aspect versions. These two 

basic cases are combined in various configurations to also obtain up to 9 aspects in a 

single signal. The three aspect signal case is configured with or without an LED or 

enameled number plate. 

To determine the part number to use when ordering a complete signal for your 

configuration or to obtain the parts list for your specific configuration, contact your 

Alstom Signaling Inc. representative. 

• Figure 7–1 shows the Type AT Signal Outer Lens and Gaskets 

• Figure 7–2 shows an example Single Aspect Type AT Incandescent Signal Unit 

drawing 

• Figure 7–3 shows an example 3 Aspect Type AT Incandescent Signal Unit with LED 

Number Plate, Ceiling/Horizontal Mount, AT000-108-01 

• Figure 7–4 shows an example 3 Aspect Type AT Incandescent Signal Unit With 


AT000-001-01 

• Figure 7–5 shows an example 3 Aspect Type AT Incandescent Signal Unit With 



• Figure 7–6 shows LED Unit P/N 20179-0XX-00 

• Figure 7–7 shows an example 2 Aspect Type AT Signal Unit With LED Light Source, 

Pole Mount, AT100-000-01 

• Figure 7–8 shows an example 7 Aspect Type AT Signal Unit With LED Light Source, 

Pole Mount, AT100-000-02 

• Figure 7–9 shows an example 3 Aspect Type AT Signal Unit With Light Source, 

Ceiling/Horizontal Mount 



Each replacement part is listed with the Alstom 10-digit drawing number that should be 

used when ordering the replacement part. 

Replacement parts are listed, described, and identified along with the quantity required 

for each assembly in Tables accompanying the figures. Screw, nut, and bolt dimensions 

are provided in diameter (inches) by threads per inch by length (inches). All other 

dimensions are provided in inches, unless indicated otherwise. 


7.3. LENSES 


Table 7-1 is provided as a quick reference of part number for the glass lens, outer bezel 

ring and the two associated gaskets only for the Colored Aspects. See the appropriate 

assembly drawing and the appropriate parts list for a complete listing of parts. 

Ring Bezel 

(outer) 

Lens Gasket 

Lens 

Bezel Gasket 

AT Housing 

Screw & 

Lockwasher 

Figure 7–1. Replacement Outer Lenses and Gaskets 

Table 7–1. Replacement Outer Lenses 

Description 

Drawing Number 

Red Lens 31624-006-00 

Green Lens 31624-008-00 

Yellow Lens 31624-007-00 

Lunar White Lens 31624-015-00 

Lens Gasket 13014-660-00 

Bezel Gasket 13014-661-00 

Bezel Ring 43983-055-00 






7.4. SINGLE ASPECT TYPE AT INCANDESCENT SIGNAL UNIT WITH TRANSFORMER 

Figure 7-2. Example Single Aspect Type AT Incandescent Signal Unit With Transformer, 


P2502, Rev. Apr/08 7–5 / 7–6 Blank Alstom Signaling Inc.


Table 7–2. Example Single Aspect Type AT Incandescent Signal Unit With Transformer, 

AT007-000-02 Part Numbers 

Ref. Description QTY Drawing No. 

1 Case Comp 1 AT004-000-01 

2 Lens (Yellow) 1 31624-007-00 

3 Receptacle Comp 1 53058-046-01 

4 Ring, Bezel 1 43983-055-00 

5 Gasket, Bezel Ring 1 13014-661-00 

6 Washer, .250 ID, .478 OD, .028 Thk Shk’prf 4 53029-075-00 

7 Screw, .250-20 x 1.25 Lg Pan Hd 4 03615-040-ON 

8 Gasket, Lens 1 13014-660-00 

9 Screw, .190-32 x .500 Lg Pan Hd 2 03610-116-ON 

10 Washer, .203 ID, .725 OD, .060 Thk Flat 2 05046-025-00 


THE FOLLOWING PART MUST BE SPECIFIED ON ORDER AND SHIPPED 

SEPARATELY 

Lamp, 10V-5W 6 34866-038-00 






7.5. 3 ASPECT TYPE AT INCANDESCENT SIGNAL, CEILING/HORIZONTAL MOUNT 

Figure 7-3. Example 3 Aspect Type AT Incandescent Signal Unit 

Without Transformers, With Illuminated LED Number Plate, Ceiling/Horizontal Mount, 




Table 7–3. Example 3 Aspect Type AT Incandescent Signal Unit Without Transformers, 

With Illuminated LED Number Plate, Ceiling/Horizontal Mount, AT000-108-01 

Part Numbers 


1 Signal Unit Comp., 3 Indication 1 AT005-000-06 

15 Plug, Pipe 1.50 1 36174-001-00 

17 Bracket, With 1.50 N.P.T. 2 35656-005-00 

20 Washer, .500 ID, .869 OD, .125 Thk Lock 6 01273-010-ON 

21 Washer, .563 ID, 1.250 OD, .078 Thk Flat 12 01250-021-ON 


26 Bolt, .500-13 x 3.50 Lg Hex Hd 1 00520-005-ON 

27 Nut, .500-13 x .594 Thk Elastic Stop 3 42333-050-00 

28 Nut, .500-13 x .438 Thk Hex 1 01048-005-00 

40 Support Comp., No. Plate 1 39751-018-02 

41 Screw, .190-32 x .63 Lg. Pan Hd. 4 03610-120-ON 

42 Washer, .190 ID, .500 OD, .031 Thk. Flat (Nylon) 8 00493-354-00 

43 Washer, .200 ID, .438 OD, .037 Thk. Flat 8 01250-009-ON 

44 Nut, .190-32 x .24 Thk. Elastic Stop. 4 42333-047-00 

52 Washer, .512 ID, .875 OD, .045 Thk. Shk’Prf. 2 53029-078-00 

53 Gasket, .06 Thk., 70 Durometer, Neoprene (Case 

Ends) 

2 13014-680-00 

56 Bolt, .500-13 x 2.75 Lg Sq. Hd W/Hex Nut 7 00525-002-ON 

57 Bracket Comp. 1 55478-021-01 

58 Bolt, .500-13 x 1.50 Lg Sq. Hd & Hex Nut 2 42187-000-00 


THE FOLLOWING MATERIALS ARE ALSO REQUIRED FOR ASSEMBLY. 

Terminal, .250 Ring (16-14) 6 59825-174-00 

Wire, #14 Flex, 600V (Per 82E0005) 6 80551-051-01 

Mineral Based Oil (Per 91A0007) As Req’d ---- 

Tape, Vinyl (Per 99F0001) As Req’d ---- 

Acrylic Paint, Black Fed. Color #37038 (Per 

92A0029) 

As Req’d 81361-151-01 

Wiring Diagram (Suffix No. As Spec) 1 Print 43989-619-00 

Soft Mastic Sealing Compound (Per 90B0010) As Req’d 81361-050-06 

Drilling Diagram, Bracket For Horiz. Mtg. 1 Print 54655-003-00 



Table 7–3. Example 3 Aspect Type AT Incandescent Signal Unit Without Transformers, 

With Illuminated LED Number Plate, Ceiling/Horizontal Mount, AT000-108-01 

Part Numbers (Cont.) 


THE FOLLOWING PART IS TO BE SPECIFIED ON S.O. AS REQUIRED. 

32 Number Plate, Enamel, Brkt. Mtg. (Spec. on S.O.) As Req’d 45924-028-00 

39 Board Assembly, LED “5” (White, Spec. on S.O.) As Req’d 31166-288-03 







THE FOLLOWING PART IS INCLUDED IN THE ASSEMBLY BUT MUST BE 

SPECIFIED ON S.O. AND SHIPPED SEPARATELY 

Lamp, 10V-5W 8 48088-031-00 



7.6. 3 ASPECT TYPE AT INCANDESCENT SIGNAL, WALL MOUNT 


With Transformers, Enameled Number Plate, Door Stop and Side Plate, Wall Mount, 




Table 7–4. Example 3 Aspect Type AT Incandescent Signal Unit 




1 Signal Unit Comp, 3 Indication 1 AT005-000-01 

5 Washer, .250 ID, .487 OD, .062 Thk. Lock 2 01273-025-ON 



15 Plug, Pipe 1.50 1 36174-001-00 



18 Bracket 1 35656-006-00 


21 Washer, .563ID, 1.250 OD, .078 Thk Flat 16 01250-021-ON 




28 Nut, .500-13 x .438 Thk Hex 1 01048-005-00 

29 Gasket, .25 Thk. Square 1 13014-685-00 

30 Washer, .190 ID, .500 OD, .032 Thk. Nylon 8 00493-354-00 

36 Gasket 1 13014-201-00 


48 Spacer, .38 Lg. Tubular 4 49655-260-00 




Ends) 

2 13014-680-00 

54 Door Stop 1 38319-002-00 

55 Screw, .250-20 x 1.00 Lg. Hex Hd. 3 54972-008-00 


57 Washer, .265 ID, .478 ID, .028 Thk. Shk’prf 6 53029-075-00 

58 Gasket, (.019) .5mm Thk. Metric High Grade, 

70 Durometer, 1500 psi Tensile Strength, 

Neoprene, (For Door Stop) 

1 13014-676-00 

59 Nut, .250-20 x .31 Thk. Elastic Stop 3 42333-048-00 





AT000-001-01Part Numbers (Cont.) 



Terminal, .250 Ring (16-14) 4 59825-174-00 

Wire, #14 Flex, 600V (Per 82E0005) 7.0 80551-051-01 




92A0029) 

As Req’d 81361-151-01 


Drilling Diagram, For Ref. 31, L Side 1 Print 54655-009-00 

Soft Mastic Sealing Compound (Per 90B0010) As Req’d 81361-050-06 

Drilling Diagram, For Door Stop, Ref.54 1 Print 54655-002-00 

THE FOLLOWING PARTS TO BE SPECIFIED ON S.O. AS REQUIRED. 

31 Number plate, Lever As Req’d 45924-018-00 

32 Number Plate, Enamel As Req’d 45924-016-00 



Lamp, 10V-5W 6 34866-038-00 



7.7. 3 ASPECT TYPE AT INCANDESCENT SIGNAL, POLE MOUNT 


With Transformers, Enameled Number Plate, Door Stop and Side Plate, Pole Mount, 



Parts Catalog 







6 Washer, .266 ID, .500 OD, .031 Thk Flat 2 01250-011-ON 

14 Washer, .200 ID, .438 OD, .032 Thk. 4 01250-009-ON 

15 Plug, Pipe 1.50 1 36174-001-00 




21 Washer, .563ID, 1.250 OD, .078 Thk Flat 8 01250-021-ON 




28 Nut, .500-13 x .438 Thk Hex 1 01048-005-00 

29 Gasket, Square, .250 Thk. Neoprene 1 13014-685-00 

30 Washer, .190 ID, .500 OD, .032 Thk. Nylon 8 00493-354-00 

33 Socket, Pole 1 28447-011-00 

34 Screw, .500-13 x 1.25 Lg Cap Hd 3 03343-035-00 

35 Nut, .500-13 x .31 Thk Hex 3 41895-001-00 

36 Gasket 1 13014-201-00 




52 Washer, .512 ID, .875 OD, .045 Thk. Shk’prf. 3 53029-078-00 


Ends) 

2 13014-680-00 

54 Door Stop 1 38319-002-00 

55 Screw, .250-20 X 1.00 Lg. Hex Hd. 3 54972-008-00 

56 Bolt, .500-13 x 2.75 Lg Sq Hd W/Hex Nut 1 00525-002-ON 



70Durometer, 1500 psi Tensile Strength, 

Neoprene, (Door Stop) 

1 13014-676-00 


Parts Catalog 



AT000-024-01Part Numbers (Cont.) 


59 Nut, .250-20 X .31 Thk, Elastic Stop 3 42333-048-00 


Terminal, .250 Ring (16-14) 4 59825-174-00 

Wire, #14 Flex, 600V (Per 82E0005) 7.0 80551-051-01 




92A0029) 

As Req’d 81361-151-01 


Drilling Diagram, For Ref. 31, L Side 1 Print 54655-009-00 

Drilling Diagram, For Door Stop, Ref.54 1 Print 54655-002-00 


31 Number plate, Lever As Req’d 45924-018-00 

32 Number Plate, Enamel As Req’d 45924-016-00 


31 Plate, Number, Enamel Side Mtg. (Spec No. On 

S.O.) 

32 Plate, Number, Enamel Front Mtg. (Spec No. On 

S.O.) 

As Req’d 45924-018-00 

As Req’d 45924-016-00 



Lamp, 10V-5W 6 34866-038-00 

60 Base Comp, Split (Cast Iron) 1 43951-003-06 

61 Pole, 3.00 Std Commercial Steel As Req’d ---- 


7.8. LED UNITS 

Parts Catalog 

Figure 7-6. LED Unit P/N 20179-0XX-00 

Table 7-6. LED Unit Part Numbers 

LED Color 

Alstom Part Number 

Red 20179-009-00 

Green 20179-008-00 

Yellow 20179-010-00 

Lunar White 20179-011-00 


Parts Catalog 



Parts Catalog 

7.9. 2 ASPECT TYPE AT SIGNAL UNIT WITH LED LIGHT SOURCE, POLE MOUNT 

Figure 7-7. Example 2 Aspect Type AT Signal Unit With LED Light Source, Pole Mount, 

AT100-001-00 Sheet 1 


Parts Catalog 




Parts Catalog 

Table 7-7. Example 2 Aspect Type AT Signal Unit With LED Light Source, Pole Mount, 



1 Signal Complete, “AT” (Red LED) Cast Alum. 2 AT200-001-01 

5 Gasket, .06 Thk. 70 Durometer Neoprene 

(Case Ends) 

3 13014-680-00 

MOUNTING HARDWARE 

17 Bracket, Top (Blank) 1 35656-006-00 




26 Bolt, .500-13 x 3.50 Lg Hex Hd Tap (Gnd 

Stud) 

2 00520-005-ON 


28 Nut, .500-13 x .438 Thk Hex 5 01048-005-00 

33 Socket, Pole 1 28447-011-00 


35 Nut, .500-13 x .31 Thk Hex 3 41895-001-00 


56 Bolt, .500-13 x 2.75 Lg W/Hex Nut 7 00525-002-ON 

70 Screw,.500-13x2.75 lg Hex Hd Cap 3 03343-027-00 

FRONT NO. PLATE 

25 Screw, .190-32 x .63 Lg. Tamper Resistant. 4 01241-065-ON 


30 Washer, .190 ID, .500 OD, .031 Thk. Flat 

Nylon 

16 00493-354-00 


35 Support Comp. (Front No. Plate) 1 39751-018-02 

SIDE NO. PLATE 

41 Screw, .190-32 x 1.00 Lg. Tamper Resistant. 4 01241-059-ON 




Parts Catalog 

Table 7–7. Example 2 Aspect Type AT Signal Unit With LED Light Source, Pole Mount, 

AT100-001-01 Part Numbers (Cont.) 


DOOR STOP 

54 Door Stop 2 38319-002-00 


57 Washer, .265 ID, .478 OD, .028 Thk. Lock 6 01273-025-ON 


70 Durometer, 1500 psi Tensile Strength, 


2 13014-676-00 



63 Nut, .242-24 x .188 Thk. Hex 4 42839-005-00 

64 Washer, .266 ID, .563 OD, .040 Thk. Flat 6 01225-002-00 

THE FOLLOWING MATERIALS ARE ALSO REQUIRED FOR ASSEMBLY: 

Terminal, .250 Ring (16-14) 4 59825-174-00 


Mineral Base Oil (Per 91A0007) As Req'd 

Soft Mastic Sealing Compound (Per 

90B0010) 


92A0029) 

Tape, Vinyl (Per 99F0001) As Req'd 

Tubing, Spiral Wrap (Per 82P0001) As Req'd 

As Req'd 81361-050-06 

As Req'd 81361-151-01 

Drilling Diagram, For Door Stop (Ref.54) 1 Print 54655-002-00 

Wiring Diagram 1 Print 43989-799-00 

Wire, #6 Copper 1 80613-000-01 

Terminal, Solder .500 Ring 2 59825-089-00 

Tag, Wire Marker, DL (ARG1) 1 34558-783-00 


Tag, Wire Marker, DL (BRG1) 1 34558-785-00 


Tag, Wire Marker,#6 AWG (GND) 2 48932-016-00 

Tie, Cable (For GND Tags) 2 01232-013-ON 


31 Plate, Number, Enamel Side Mtg. (Spec No 

On S.O.) 

1 45924-018-00 


Parts Catalog 

Table 7–7. Example 2 Aspect Type AT Signal Unit With LED Light Source, Pole Mount, 



32 Plate, Number, Enamel Front Mtg. (Spec No 1 45924-028-00 

On S.O.) 

THE FOLLOWING PARTS ARE INCLUDED IN THE ASSEMBLY, BUT MUST BE 

SPECIFIED ON S.O AND SHIPPED SEPARATELY 

60 Base Complete, Split (Cast Iron) 1 43951-003-06 

61 Pole, 3.00 Std. Commercial Steel 1 11560-163-00 

65 Hood 4” 2 49127-108-00 


Parts Catalog 



Parts Catalog 

7.10. 7 ASPECT TYPE AT SIGNAL UNIT WITH LED LIGHT SOURCE, POLE MOUNT 




Parts Catalog 




Parts Catalog 

Table 7-8. Example 7 Aspect Type AT Signal Unit With LED Light Source, Pole Mount, 








17 Bracket 1 35656-006-00 






28 Nut, .500-13 x .438 Thk Hex 6 01048-005-00 

29 Gasket, Square, Neoprene, .250 Thk. 2 13014-685-00 

33 Socket, Pole 1 28447-011-00 


35 Nut, .500-13 x .31 Thk Hex 3 41895-001-00 

36 Gasket 2 13014-201-00 


53 Gasket, .06 Thk., 70 Durometer, Neoprene 

(Case Ends) 

5 13014-680-00 

54 Door Stop 3 38319-002-00 


56 Bolt, .500-13 x 2.75 Lg Sq Hd W/Hex Nut 7 00525-002-ON 

57 Washer, .265 ID, .478 OD, .028 Thk. Lock. 9 01273-025-ON 


70Durometer, 1500 psi Tensile Strength, 


3 13014-676-00 


60 Washer, .266 ID, .500 OD, Flat 9 01250-011-ON 

61 Plate 1 54106-462-00 


67 Hood, 9” 6 49127-107-00 

68 Hood, 4” 1 49127-108-00 


Parts Catalog 

Table 7–8. Example7 Aspect Type AT Signal Unit With LED Light Source, Pole Mount, 



69 Bolt, .500-13 x 4.5 Lg Sq Hd W/Hex Nut 3 49527-034-00 

70 Screw, .500-13 x 2 3/4 Lg Hex Hd Cap 3 03343-027-00 

THE FOLLOWING MATERIALS ARE ALSO REQUIRED FOR THE ASSEMBLY 

Mineral Based Oil 

Tape, Vinyl 

As Req’d 

As Req’d 

Acrylic Paint, Black Fed. Color #37038 As Req’d 81361-151-01 

Soft Mastic Sealing Compound As Req’d 81361-050-06 

Drilling Diagram, For Door Stop Ref. 54 1 Print 54655-002-00 

Terminal, .250 Ring (16-14) 14 59825-174-00 

Terminal, Solder .500 Ring 4 59825-089-00 


Wire, #6 Copper 6 80613-000-01 

Wiring Diagram 1 Print 43989-800-00 

-- Tag, Wire Marker, DL (ARG1) 1 34558-783-00 




Tag, Wire Marker, DL (AHG1) 1 34558-793-00 

Tag, Wire Marker, DL (AHG2) 1 34558-794-00 

Tag, Wire Marker, DL (BHG1) 1 34558-795-00 

Tag, Wire Marker, DL (BHG2) 1 34558-796-00 

Tag, Wire Marker, DL (CHG1) 1 34558-797-00 

Tag, Wire Marker, DL (CHG2) 1 34558-798-00 

Tag, Wire Marker, DL (ADG1) 1 34558-799-00 

Tag, Wire Marker, DL (ADG2) 1 34558-800-00 

Tag, Wire Marker, DL (BDG1) 1 34558-801-00 

Tag, Wire Marker, DL (BDG2) 1 34558-802-00 

Tag, Wire Marker,#6 AWG (GND) 4 48932-016-00 

Tie, Cable (For GND Tags) 4 01232-013-ON 

THE FOLLOWING PARTS TO BE SPECIFIED ON S.O. AS REQUIRED 

32 Plate, Number, Enamel, Front Mtg. (Spec. 

No. On S.O.) 

As Req’d 45924-016-00 


Parts Catalog 

Table 7–8. Example7 Aspect Type AT Signal Unit With LED Light Source, Pole Mount, 



THE FOLLOWING PARTS ARE INCLUDED IN THE ASSEMBLY, BUT MUST BE 


63 Base Comp, Split (Cast Iron) 1 43951-003-06 

71 Pole, 3.00 Std Commercial Steel 1 11560-166-00 


Parts Catalog 



Parts Catalog 

7.11. 3 ASPECT TYPE AT SIGNAL UNIT WITH LED LIGHT SOURCE, CEILING/HORIZONTAL MOUNT 

30 

32 

29 

53 

14 

38 

25 

60 

(NOTE 10) 

22 

27 

DETAIL "K" 

METHOD OF INSTALLING BRACKET (REF.29) 

AND FRONT NO. PLATE (REF.38) 

AT BOTTOM OF SIGNAL CASE 

53 

20 

56 

21 

(2.50) 

NOTE 12 

53 

53 

SEE 

DETAIL 

"A" 

SEE 

DETAIL 

"A" 

(Ø.875) 

17 

53 1 

39 

38 

DETAIL "K" 

"E" 

DETAIL "A" 

VIEW SHOWING METHOD OF 

ASSEMBLING NUTS, WASHERS, 

ETC., AT TOP OF SIGNAL CASE 

21 

20 

56 

DETAIL "D" 


ASSEMBLING NUTS, WASHERS, 

ETC., AT BOTTOM OF SIGNAL CASE 

SEE 

DETAIL 

"A" 

15 

SEE 

DETAIL 

"C" 

( 28.75 ) 

( 33.93 ) 

"E" 

SEE 

DETAIL 

"K" 

SEE DETAIL "D" 

EXCEPT ADD WASHER 

REF.52 UNDER HEAD 

OF BOLT 

VIEW "E-E" 

VIEW SHOWING BRACKET REF.17 

AT BOTTOM OF SIGNAL 

SEE 

DETAIL 

"K" 

17 

SEE 

DETAIL 

"D" 

28 

22 

NOTE 11 

NOTE 12 

26 

DETAIL "C" 


ASSEMBLING GROUND POST 

20 

27 

21 

53 

52 

Figure 7-9. Example 3 Aspect Type AT Signal Unit With LED Light Source, 

Ceiling/Horizontal Mount 


Parts Catalog 

Table 7-9. Example 3 Aspect Type AT Signal Unit With LED Light Source, 

Ceiling/Horizontal Mount Part Numbers 


1 Signal Unit Comp., 3 Indication 1 70408-002-02 

2 Signal Unit Comp., (Red) 1 70408-003-01 



15 Plug, Pipe 1.50 1 36174-001-00 


17 Bracket 1 35656-006-00 







28 Nut, .500-13 x .438 Thk Hex 1 01048-005-00 

29 Gasket, .25 Thk. Square 1 13014-685-00 

36 Gasket 1 13014-201-00 


53 Gasket, .06 Thk., 70 Durometer, Neoprene 

(Case Ends) 

3 13014-680-00 

54 Door Stop 2 38319-002-00 

55 Screw, .250-20 x 1.00 Lg. Hex Hd. 6 54972-008-00 


57 Washer, .265 ID, .478 ID, .028 Thk. Shk’prf 12 53029-075-00 


Parts Catalog 



Drawings 

A. APPENDIX A – DRAWINGS 

A.1. GENERAL 

The following are sample wiring diagrams for basic AT LED (no LED number plate). 

Dashed lines indicate field installed wiring. 

A.2. TYPE AT INCANDESCENT SIGNAL WIRING DIAGRAMS 

ACX 

R 

Figure A–1. Typical Single Aspect Type AT Incandescent Signal Wiring Diagram 

P2502, Rev. Apr/08 A–1 Alstom Signaling Inc.

Drawings 

G 

Y 

R 



110 VAC 

COMMON (BCX OR ACX) 

LAMPS 

TRANSFORMERS 

TERMINAL 

BLOCK 

BLACK 

BCX 

ILLUM 


R Y ACX G 

RED 

TYPICAL WIRING OF A 

LAMP AND TRANSFORMER 

Figure A–2. Typical 3 Aspect Type AT Incandescent Signal Unit With Illuminated 

Number plate and Transformers Wiring Diagram 


Drawings 

Figure A–3. Typical 4 Aspect Type AT Incandescent Signal Unit 

With Enameled Number Plate and Transformers Wiring Diagram 

(Single Aspect Plus 3 Aspect) 


Drawings 

A.3. TYPE AT SIGNAL UNIT WITH LED P/N 20179-0XX-00 WIRING DIAGRAMS 

L 

1 

2 

CX 

L 

Figure A–4. Typical Single Aspect Type AT Signal With LED Unit P/N 20179-0XX-00 

Wiring Diagram 


Drawings 

G 

1 

2 

Y 

1 

2 

R 

1 

2 

xxxRG 

xxxHG 

ACX 

xxxDG 

Figure A–5. Typical 3 Aspect Type AT Signal With LED Unit P/N 20179-0XX-00 Wiring 

Diagram 


Drawings 

G 

1 

2 

Y 

1 

2 

R 

1 

2 

20 

1 

2 

xxxSTG 

xxxRG 

xxxHG 

ACX 

xxxDG 

Figure A–6. Typical 3 Aspect Type AT Signal With LED Unit P/N 20179-0XX-00 and 

Illuminated Number Wiring Diagram 


Drawings 

1 

2 

1 

2 

1 

2 

1 

2 

BXAR AR BXBY AY BXAY BY BXBR BR 

Figure A–7. Typical Four Aspect Type AT Signal With LED Unit P/N 20179-0XX-00 

Wiring Diagram (Single Aspect Plus and 3 Aspect) 


Drawings 



FOR QUESTIONS AND INQUIRIES, CONTACT CUSTOMER SERVICE AT 

1-800-717-4477 

OR 

WWW.ALSTOMSIGNALINGSOLUTIONS.COM 

ALSTOM SIGNALING INC. 

1025 JOHN STREET 

WEST HENRIETTA, NY 14586

Type AT Signal - Alstom

Create successful ePaper yourself

Delete template?

Save as template?