Isn't that why there's facilities like Wildenrath? Did Stadler use such a faculty for testing before delivery?
That is indeed why such facilities exist. I think the 755s have gone to Velim for their initial tests?
Either way, the situation that's now seen with the 755s clearly hasn't occured during testing. Perhaps it only manifests itself under very specific circumstances?
But track circuiting is pretty standard isn't it? If it's a rail/wheel contact issue causing lack of track circuit detection you'd expect that to manifest itself elsewhere too.
The principle is the same but the way it's implemented in countries can be slightly different. Different voltages / frequencies for example. That's why local testing happens next to test tracks.
The level crossing incident is odd. If the train "disappeared" before passing the crossing, but after the barriers had come down, surely the fail safe design is for the barriers to stay down?
If the level crossing is activated only by a track circuit becoming occupied, then it's not unexpected for the crossing to consider the track free when the TC no longer detects the train.
The fail-safe design in a track circuit is to show the block as occupied when a failure occurs, which would lower the barriers. In this case obviously something went wrong causing the TC to incorrectly think the block is free.