Hi, there is no off the shelf match for rail blue, but I did obtain the RAL and BS codes for rail blue, yellow, grey and the intercity and railfreight greys.
An online company called CJ aerosols will fill a can with any colour, just give them the code. I brought so much rail blue off them, they now sell it as rail blue! And you have a choice of matt, gloss or semi!
They are on the web.
Regards