Journal of Accident Investigation

and the FRA stated that they expect that high-speed railway
service would commence in 2006.
Amtrak
Bob Kollmar presented information about Amtrak’s
Incremental Train Control System (ITCS), which supports
revenue service operating up to 90 mph on 4 track miles between
Chicago and Detroit. The ITCS has a GPS location system and
an on-board computer system that provide information about
track restrictions, additions, curves, and temporary slow orders,
as well as supervising movement and enforcement of the train.
The on-board display shows track speed limit, actual train speed,
target future speed, time until override, distance to home signal,
milepost number, and train type.
The ITCS is designed to prevent trains from exceeding speed
limits (permanent and temporary), encroaching into the work
limits of roadway workers, and colliding with one another. The
ITCS has developed braking algorithms based on “worst case
scenarios.” For example, Kollmar described a test in which a
heavy Norfolk Southern freight train was run downhill with
disabled dynamic brakes. The train engineer was instructed not
to use the controls, and the ITCS overrode the controls and
stopped the train as designed. Their testing has passed FRA
standards for both passenger and freight and, based on their
success, Amtrak has requested to increase train speeds to 9
and 100 mph.
Steve Alleman of Amtrak described another system they
have implemented on the Northeast Corridor known as
the Advanced Civil Speed Enforcement System (ACSES).
Originally developed in Europe, ACSES is a “vital overlay”
system that has been implemented incrementally using existing
signals. ACSES has been used on the high-speed Amtrak
Acela trains between New York City and Boston since 2000. Its
current capabilities include positive train stop at interlocking
signals and radio release of signals. Currently, Amtrak is
working on enforcement of temporary speed restrictions using
PTC. However, during testing of the phase-two system, they
encountered difficulties, which led them to shut the system
down. Alleman noted that they have learned to keep the system
specifications as simple as possible, to standardize on-board
equipment as much as possible, and to have precise location
data at the outset of the project.
Alaska Railroad
Eileen Reilly and Andy Schiestl presented information about
the Alaska Railroad’s Collision Avoidance System (CAS).
Development of CAS began in 1997 with the primary goal of
train separation. Other goals included increasing train speed,
capacity, and efficiency, and having a paperless system. Because
Alaska Railroad has no power on much of its track, they felt it
couldn’t support a “big infrastructure” system.
The CAS system consists of a main computer,
on-board displays, dispatcher displays, locomotive polls
at waysides to provide on-board data, and speed/distance
evaluation brakes. The system allows for remote control of
siding switches to keep trains at a safe distance from each other
using GPS technology. On-board computers in locomotives
monitor the status of the switches and show train movement
instructions to the crew. Alaska Railroad has also installed
a computer-aided dispatch system and converted its analog
microwave communication system to digital. Prototype CAS
equipment is scheduled to be installed in the spring of 2006 on
a test locomotive, and a braking test of the collision avoidance
system is scheduled to begin in the fall of 2006.
NTSB JOURNAL OF ACCIDENT INVESTIGATION, SPRING 2006; VOLUME 2, ISSUE 1 77
CSX
Denise Lyle from CSX provided a freight rail perspective and
discussed the CSX Communication Based Train Management
(CBTM) system. According to Lyle, CSX has not set a goal of
zero collisions, but has addressed areas of highest risk. CBTM
is an overlay safety enhancement system, currently designed
for nonsignalized territory. The system relies on existing signal
technology to make sure that crews comply with authorities or
speed restrictions that they have been given. The system will
notify a crew as they approach work zones, speed restrictions,
or the end of the train’s authority. If the crew does not respond,
the system will provide a penalty brake override. According to
Lyle, if the CBTM system fails, it will return to its original level
of operation, which places primary responsibility of train control
on the crew.
Burlington Northern Santa Fe Railway
POSITIVE TRAIN CONTROL SYSTEMS
Rick Lederer from the BNSF presented information about
the BNSF Electronic Train Management System (ETMS).
This overlay system provides a “safety net” while other systems
maintain primary control. Like other systems, the train receives
communications from signals as it approaches them, and in-cab
computers provide information about the upcoming signal. If
the crew approaches a signal without slowing, the signal will
send a message to the in-vehicle system to begin automatic
braking. Currently, the system covers 22,000 track miles, with
8,000 to 10,000 thousand that remain to be covered, mostly in
single train branch lines.