Train show

We went to the train show in Chicago, which was kind of a bust for most of us. They had a lot of stuff for didn't really have much of anything that we were looking for, and it was several buildings of stuff I didn't want. But at least I know now.
I did pick up a loco I've been wanting to get for a while, an E6 diesel passenger loco. Very streamlined.

Only one small problem. When I put it on the tracks and powered up, only the lights worked. It didn't move, or even make an electric buzz like current was getting thru. This is the only dud I've bought at a show, so I'm willing to chalk it up to random chance.
Because the lights worked, it was (hopefully) a minor wiring problem. I checked the wires running through the chassis, and found one of the motor leads wasn't attached to the motor, apparently due to a bad solder joint. (In the picture where I'm holding the circuit board, the red wire hanging off by itself should be attached to the brass motor lead that looks like a small backwards "L" in the center of the motor close-up photo. Obviously not.)

Apparently a simple problem with a simple fix? Will it work? It should, basic electric motors like this are only a handful of color coded wires taking power to and from the motor. I've never had to attempt a repair like this, but hey, there's a first time for everything. The soldering iron is heating up as I type this. Will I be able to attach the wire without melting the plastic motor mounts? Will the loco run after this, or is the loose wire only a sign of more problems I haven't discovered yet? Hopefully, I'll have good news in a little while.