Locomotive doesn't move

[pilot2fly]

Hi there,

I recently purchased a brand new Bachmann SD40-2 CSX DCC Sound Value locomotive. The locomotive worked great when I first got it. I used it twice for about a total of 10 minutes, then reboxed it. Everything worked fine. I later tried it and now the locomotive doesn't move at all. However, sound and lights still work.

There's no short on the track, and other locomotives work just fine on the track. Voltage is good too. Locomotive simply won't move no matter what I do.

Any help or suggestions?

[Hunt]

Start over -
Reset the decoder
     Program CV 8 with 8
     Turn power off then on to track

Locomotive address after decoder reset is 3 or 03 depends on DCC system being used.

[Jelle]

When you remove the body, review the four electrical wires to the wheels.
Probably they are too short, and are stressed when turning the bogies. 
The bogies can pull these wires loose from the contacts after making sharp curves.

The train might not work at all, or will derail when only one motor is operating, so one might think it's a rail problem.

[bbmiroku]

Or a piece of grit got in somewhere.  Try forcing the wheels to turn while the speed is on low.  I always go for a physical problem before an electrical one.

[Trainman203]

Bachmann service department? 🤔