I’ve just rejoined the forum.
Bob Jones did an etch of generic 5’3” chassis from 8’6” wheelbase to 12’0”. He might be prepared to do one for you.
I’m currently trying to design a mechanism for the railcar using a 3mm motor from Nigel Lawson and some Modulo3 gears which I have just picked up at the show in Friedrichshafen Germany
if I can help, I’ll drop back in when I get home
regards
David Wynne