More importantly, did you check the drawbar connection between engine and tender?
2 ways this can be a problem:
#1 just not seated fully at the tender side. This can uncouple over time and running so there are options for a drawbar lock- just something slid over the tender drawar post to hold the drawbar PCB in place. In fact, MTH has a part for this. https://ogrforum.ogaugerr.com/...wbar-issues-solution
FB0000037
https://www.mthpartsandsales.com/shop/search
Alternate tubing method
#2 In quite a few steam engines, I have seen the wiring harness was pulled tight from the factory and ziptied and this can cause the connector at the engine side of the drawbar to unplug as the drawbar swings and with usage. Opening the engine shell and cutting the ziptie (or in rare circumstance), just slide a little more wire for a loop and free slack.
Again, at the engine side of this, I have seen the drawbar wiring harness pulled too tight from the factory with no slack and it unplugs into the drawbar.
