I have the MTH 4-6-2 Blue Comet a P47 Baldwin. She has been running like a champ since getting the board replaced however a brand new issue has appeared. On my layout I have a basic oval with 2 atlas o-54 switches before the o-54 curve to the oval. The engine had no issues previously but yesterday while running the engine I had noticed the rear truck hopping and various points on both o-54 switches on either side of the layout. Sometimes the truck will right itself and let the train continue down the track. Other times it will derail the rear drive wheels. Nothing about my layout has changed which is why i am perplexed as to why this is happening now. I have a couple of diesel locomotives that can go through all of my atlas o-54 switches without issues at any speed but the steamer can only pass through at 5 scale mph about 80% of the time without the rear truck lifting.
Furthermore I set up the same problem switches and extended them with straight track to see if the steamer would pass without any issues and it does. I wasn't able to test it at any speed however due to limited space. I still think it may be an issue with the rear truck not fully resetting but i am at a loss. Any insight or experience would be greatly appreciated!