The procedure is on page 27 of the manual assuming it’s a GP-30
If your locomotive is unresponsive to your commands in the Command Control environment, we recommend that you follow this procedure to reset your locomotive. All factory default settings will be restored when you reprogram the locomotive.
1. Slide the program run switch to the PGM position.
2. Plug in and connect your LEGACY Base or TMCC Command Base. 3. Place your locomotive on the track, then power up the track.
4. Press ENG and enter the locomotive’s ID#.
5. Press SET.
6. Turn off track power and wait ten seconds.
7. Slide the program run switch back to the RUN position.
At this point, your locomotive has been reset. Restore power to the track and operate the locomotive as usual. Be sure to use the ID# entered in Step 4.