The error seems to have happened because the national rail operator RFF gave the wrong dimensions to train company SNCF.

Our correspondent says that they measured platforms built less than 30 years ago, overlooking the fact that many of France’s regional platforms were built more than 50 years ago when trains were a little slimmer.

This is a prime example of a bug which would have been an awful lot cheaper to fix had it been caught at the design phase of the project.