I have o gauge trains that are old. I hooked them up-you see lights - but train won't run. Why?

Question

You can see sparks and it hums. I have 3 locomotives and 3 transformers. All give same results on my 3 rail O gauge track

Answer 1

Why ?? Dirt, Tarnish, Crud !!

The first thing to do is to clean the tracks... a "Bright Boy" block from a hobby shop is what I use for HO and N scale track.  I'm sure there is something out there for the O-scale community.

Since you mention the Locomotives themselves are old, I'd also suggest cleaning them:  Remove the body, use canned-air to blow out any dust from the motor and gearing, use q-tips and rubbing alcohol (or electronics cleaner) to clean the wheels and contact points.

GOOD LUCK !!