I've run into a bug with 2 scenarios now where there is no power to the train if you save and resume. This is for the scenarios 'Powering America Parts 1 & 2'. The train has sound as if it has power, but there is no output. Even if you stop and take everything back to the beginning (reverser, power, brakes), the only way to fix it is to restart the scenario.
I'm not planning to go up to TSW4. I just ended up going back to TSW2 for now. Just weird that the same scenarios are in both but only TSW3 has the bug. I do like the concept of the 'I'm Stuck' button though. As a work-around, I just won't save in TSW3 but it's weird that the solution to a bug in a feature is to not use the feature.