As someone who is involved with procurement (not on railways, I hasten to add) "... unless you can detail massive experience in successfully delivering previous similar contracts..." has nothing to do with EU procurement laws. That is what most clients request though, why would you want to go to someone who has never done 'it' before or has a bad track record?
It has a little bit to do with EU procurement law in the sense that the criteria you can apply at the selection (shortlisting) stage is quite limited and, if you want to qualitatively compare candidates to arrive at a shortlist, experience is one of the only ways to do this, especially when all bidders are likely to meet the financial standing requirements.