I don't know if I was clear there, sorry!
Carl painted the entire current/recent fleet which works in Extended or for experienced players but would not suit this. It's too many choices with not enough difference that players will understand what's going on.
Instead I would offer speed/capacity/cost choices - perhaps 3/4 choices per "type" of vehicle (trucks, EMU, DMU, coaching stock, plane, boat) per "era". That way there would be no more than around 10-15 vehicles at any one time (and that's for trains where EMU/DMU/Coaching stock are all very different anyway), boats, planes and cars would be much lower
I think, properly balanced, it would help players understand the choices they have to make without being faced with 70+ types of vehicle per type to pick from.
For what it's worth, once I've fleshed out my pakset I will give doing a smaller fork like you have suggested. It's still pre-alpha so you g enough that it would be easy and involve little effort.