The differences I can see are, the non Railroad version has...
1 OHL sticker,makers plate on smoke defelctors
2 Painted handrails on deflector (maybe wire on production version)
3 White boiler handrails
4 Painted ends on cylinders and drain
cocks
5 Painted pipe on boiler
6 Ohl sticker cb end of boiler
7 Lined drivers window
8 Pretty yellow axle boxes
9 Lining on cab sides and tender has black painted centre line.
Not a lot for 50% price increase, easy to paint 2,4,5 and
8. If you want an early BR you dont need the OHL stickers. They both seem to have speedo cables and cab glazing. RR version for me!