The second accident on 29 September caused injuries, high material damages and a major train service disruption.
Stuttgart Hbf is a terminus railway station, except for S-Bahn (commuter rail) trains and underground trams.
To make room for the construction site, the platforms had to be moved away from the current station building.
The tracks also had to be closed for the rescue to begin, and both actions separated the entire station from the network for hours.
[2]: 13 On 9 October 2012, three test runs were initiated in addition to software-based simulations to support the investigation, and indeed, the last try reproduced the derailments.
[2]: 53 The track layout was shown to have some deficiencies regarding the sequence of curves, specifically straight elements inside S-curves.
The combination of track elements within a small area had taken them to the allowable limits, increasing wear and reducing stability.
Also, track distortions and wear had been found before the first accident, but had not been rectified, or had not been recognized due to errors.