Trolley (or any DC Bachmann engine) leaves the house, stops at the far end properly, but refuses to restart in the reverse direction. No visible glitches anywhere. Do I need to replace a circuit board? If so, where is it and how do I proceed? Any other possible troubleshooting suggestions?

I have tried using rubber stamps for lettering cars with (so far) limited success. You can have custom stamps made pretty inexpensively here:

http://www.rubberstamps.net/art-stamps.aspx

or at some office supply stores like OfficeMax, Staples, etc., and hobby stores like HobbyLobby. Stamping is a big deal with scrapbookers, among others. Look for inks meant for non-porous surfaces.

You can also buy stamp kits with individual letters and numbers at office stores; fonts are pretty limited but you can do things like reporting marks and numbers.

I have just started trying this and unfortunately my first projects were tank cars. The convex surface makes it VERY hard to get a clean impression. My fix so far is to weather the daylights out of the ones I've done, and if I ever get any I'm proud of I'll post pictures. Next ones will be flat-sided cars!