The faulty wheel design
The jury identified faulty wheel design as the root cause of the disaster: the wheel has outer and inner parts, with an elastic rubber-like material in-between – and stresses in the outer steel ring led to cracking from the inside.

Was this wheel high-tech? Not at all. It was a design taken from tramways – without testing at high speeds – as an easy solution to bad ride quality (i.e. vibrations passengers feel). But that bad ride quality was a result of saving on the use of air springs in the first-generation ICE trains – then a proven but still new technology.

Politics vs. development
The background of this saving (and some I'll tell about below) was that ICE trains were kind of a stepchild of German transport policy in the eighties, developed by the German Railways without much government support – while the toy of the big boys of the Kohl government was the Transrapid, Germany's magnetic levitation train.

The Maglev has its technological advances alright, but has some severe economic and operational problems: its track is very expensive, and while most European high-speed trains reach destinations beyond high-speed lines, you'd have to build dedicated track for the Transrapid everywhere for comparable service. But said big boys only had that glimmer in the eye, and made sure that the ICE won't steal the Transrapid's limelight. So, even tough the ICE was intended to be a much more modern train than the TGV, many key technologies were delayed until the ICE-2 or even ICE-3.

Pre-emptive detection fails
The faulty wheel could have been identified before breaking during the frequent regular checks this train has. In fact, it was! The problem is: in another cost-saving measure, the maintenance facility was only equipped with some simple hand-held devices, which were also unreliable – the workers thought the extreme value they measured was an instrument error like ones they had before.

No emergency detection
The ICE trains were originally to be fitted with on-board detection systems, which could have warned the train driver. But this was also 'saved'.

Stability after derailment
ICE trains have bogies like normal carriages – so it has widely been claimed that had the ICE had Jacobs bogies between the cars like the TGV (picture below), it wouldn't have derailed "so easily". But, in truth, the train was very stable: with a broken and derailed wheel, it travelled another 5.5 km at full speed before the disaster. In fact passengers would have fared better if the train had left the tracks after the wheel broke...

Photo from RailFanEurope.net

The train breaks apart
The onset of the disaster was when the broken wheel (the third on the first carriage behind the front tractor head) got struck in a switch. The impact tore apart the connection between the locomotive and the first car, and switched the switch to the deviating route. The train broke apart the second time between the third and fourth cars – the front tractor head rolled out (stopping 2–3 km away), the first three cars just derailed and came to halt on the tracks with minor damage, but the switch directed the rest of the train sharply to the right at 198 km/h.

A high-tech accident? Not at all: high-speed switches are designed so that nothing gets struck and its moving parts are locked – but the disaster happened on an upgraded old line, on which (cost-cutting again) not all switches were replaced...

The bridge collapses
The really big disaster came because the fourth car kicked out the pillar of a road overpass, which fell on the fifth and sixth cars and "stopped" the rest dead. How could this have happened? You guessed it, high-tech cost-cutting again: along high-speed and fully upgraded old lines, no switches are supposed to be near overpasses, and overpasses have no central pillars.

Harmonica effect
The remaining six carriages and the back tractor head curled up like a harmonica. Beyond referring to the TGV's irrelevant supposedly superior stability, newspapers often quoted 'experts' that the back tractor head made things worse by pushing up the train on the bridge's wreck.

Not true: traction stops and braking starts automatically as soon as the train breaks apart! And a basic calculation shows that to stop just the last (12th) car still intact (from 198 km/h to zero in 132 m and 4.8 seconds), something beyond 1G and a force of c. 630 kN would have been needed even for continuous deceleration! That's well beyond what the brakes could give, so even if the back tractor head at least gave to the mass to be stopped, the outcome wouldn't have been much different without it.

Bulletproof windows trap people
There was one high-tech problem that played a role: wounded victims trapped in the wreckage could not break themselves free, as the extremely strong windows weren't designed for that. The ICE's windows are very strong so that passing tunnels, especially passing other trains in tunnels, won't hurt people's ears. However, even this is a result of a cost-cutting measure (which caused other problems too): German high-speed lines were built with single-tube, two-track tunnels, rather than twin tunnels.

Previous Monday Train Bloggings:

1. (Premiere/ modern Austrian trains & locos)
2. Adventure
3. Fast Steam
4. Heavy Haul
5. Forgotten Colorado
6. The Hardest Job
7. Blowback
8. Highest Speed
9. New England Autumn