A new-generation ICE train racing up a slope along the Cologne - Frankfurt route opened in 2002.
Rail operator Deutsche Bahn is checking many of its ICE trains 10 times more frequently than usual because engineers still haven't found the cause of a broken axle that led to the derailment of an ICE train in Cologne on July 9.
Deutsche Bahn now has to service the newest ICE trains after every 30,000 kilometers, a far stricter requirement than the previous interval of 300,000 kilometers.
The checks have disrupted services for more than a week and are set to cause a prolonged period of delays on the important route linking Cologne, Frankfurt and Munich.
Trains have become heavily crowded because they're only half as long as usual along the Cologne - Frankfurt route. At present, only single trains are being used rather than the usual practice of articulating two trains. The checks are proving particularly disruptive because they include 67 ICE3 and 70 "ICE T" tilt technology trains, the latest generation of the ICE.
The ICE3 is the only train that can be used on the 180 kilometer Cologne-Frankfurt high-speed route which was opened in 2002 and which puts trains under more technical stress than any other such line in the world because it has inclines of up to 4 percent. Deutsche Bahn is the only rail operator in Europe to have built a high-speed route that can only be used by one type of train, and the company is now likely to be regretting that move.
Experts have warned that inclines as steep as the ones between Cologne and Frankfurt are dangerous, but Deutsche Bahn insists that the route poses no problems. Even the trans-Alpine routes through Austria and Switzerland have inclines of less than 3 percent and France's TGV trains don't have to master slopes of more than 3.5 percent.
Railway tracks are kept as flat as possible because there is little traction between the steel wheels and steel rails, which means trains can easily skid when accelerating or breaking on slopes. To cope with the problem, the designers of the ICE3 were inspired by Transrapid magnetic levitation technology and installed electromagnetic brakes in addition to conventional ones.
The advantage is that such brakes do not rely on friction between the wheels and rails, thus enabling trains to travel up and down steeper slopes. The disadvantage is that they put the axles under more strain, which prompted engineers to suggest that the ICE switch off the electromagnetic breaks under the heavy locomotives or even shut the toilets and empty their watertanks to lighten the trains.
Both proposals failed to impress the Federal Railway Authority, which oversees railway safety, and are unlikely to boost public confidence in the train system.
Now experts are worried about the increased weight on the axles being caused by overcrowded trains. "How can a company that seriously suggests closing toilets to decrease the weight now risk constantly running overcrowded trains?", said Horst Becker, transport affairs spokesman for the opposition Greens party in the state parliament of North Rhine-Westphalia.
These days conductors have trouble wading through the carriages past passengers standing or sitting in the corridors. But the railway is refusing to introduce a compulsory reservation system like the one the TGV operates. The additional weight of the added passengers on the shortened trains is well within tolerance limits, Deutsche Bahn says.
With reporting by Barbara Schmid and Christian Wüst