Only being able to add here from my Shunting experiences, but Loco Wise some are better than others - The EMD Designs (59/66s) aren't too bad, nor are the 47s & 57s, but the worst I've come across were the unrefurbished Class 37s - cramped at best - who thought it was a good idea to put the horn lever by your legs? Not so great when trying to couple up to another loco or coach/wagon with the long bonnet too. Height wise you might be able to see better out of the cab windows though. The DRS refurbished 37s are a little bit better but only just, although the cab soundproofing does reduce the space somewhat! 20s aren't too bad, just as long as the seat doesn't get stuck.