Just got TS2021 and have been playing with the built-in scenarios, in this case using a Swiss electric loco. I accelerate away from the station platform, the display seems to indicate a speed limit of 80 (kph I presume), but the train only ever gets to ~37 regardless of how much power I use. It's not that I want to run the thing off the track, just get the feel of having to add/reduce power depending on the grade of the section. It seems like I'm doing something wrong, but I haven't been able to figure it out.
Obvious question but bears asking- is the handbrake on? It's easy to put it on unnoticed by catching the slash key.
Swiss locos have the equivalent of cruise control. Have you set it at the speed you want? Details in the manuals.
