There's this amazing wonder material called...............................wood. 
La Belle actually sells kits for trolleys made of wood, 
Ok, now that I've worked out my snarky reply for evening........
Actually, I scratchbuild trolleys, freight motors, traction freight cars, etc and have been contributing that information on a column in another publication now for over 5 years - "O Scale Trains". I try to convey just the information that you're asking about as I provide a serialization of one project after another. And, I work in wood, styrene, resin, and even brass (not etching though)...just about nay material that does the job right.
La Belle kit:
Scratchbuilt snowplow:
