DELIVERABLE 2.8 - urban track

2.8. FRANKFURT
D0208_STIB_M24.doc
TIP5-CT-2006-031312 Page 20 of 44
URBAN TRACK Issued: August 13, 2008
Quality checked and approved by project co-ordinator André Van Leuven
VGF (Frankfurt) operates 300 km of track with a 50/50 split between grooved and vignol rail. The
introduction in 1995 of the low floor vehicles caused the same problems as in Bremen. VGF uses the
following tools:
One lubrication vehicle;
Stationary lubrication systems (which cause problems during welding);
Resilient wheels on vehicles operating in the city.
Since 1988 they use the same welding technique as in Brussels on rails with low carbon content.
They use Riflex (Electrothermit) of 1700 N/m with Q800 on the top of the rail to combat corrugation and
ETEKA 5 of 1400 N/m on the side of the rail to combat wear. The problem is the splitting off of the weld
under the vertical wheel load. The Riflex was ground away and the rails finished with Citorail (= DUR
300).
This technique had the following problems:
The rails are not machined for the pre-emptive welding, but grooves are burned out. Therefore the
rails have to be carefully cleaned. Otherwise, the welds easily break out of the rail head.
The material characteristics change during the heating process (e.g. rail welding). This produces a
surface with inconsistent properties that results in weak spots (20 cm each side of the weld) and
variations in the rail height.
The material easily breaks away from the rail head and requires frequent weld repairs and frequent
grinding after the repairs.
The method requires a lot of attention and is very costly.
In 1998 they worked with perlitic vignol rail with Q1100 on the outer rail and Q880 on the inner rail.
Grooved head hardened rail had to be removed after the welding of the lip which caused the lip to break-
off. Currently they use Ri59 and Ri60 of Q700.
The rails are installed as delivered and wear reaches 7 mm after only 6 months. Wear increases both on
the head and on the lip and reaches 12 to 15 mm after 14 months. They use the same welding material as
in Bremen. UGF also has flange lubrication installed on 20 vehicles.
The cost of rail replacement is 1400€ per m; build-up welding 80€ per m and normal rail welding 80€ per
weld.