Not sure if these work arounds work on all platforms, but so far it works for the PC editions. Work around 1: Reversing back to the Coal Chute at around 10mph seems to do the trick, Though it's not 100% guaranteed! This is a short video that I created showing the derailment, followed by a successful run. Work around 2: This is another option where you take a different route, which puts you on the approach from behind the coal chute. If you take the route of the path I have marked in green, this will take you up the Return Loop bringing you up behind the coal chute. Though it does work, It isn't as reliable as reversing at 10mph. Tip: Before reversing, it's a good idea to save the game. So that if derailing does occur, you don't have to start the scenario from the beginning
I just did it with low speed, and the scenario worked without any derailments. I'm on PC (Epic). Maybe it's something to do with your reverser position? At the beginning, the scenario suggests leaving the reverser around 25, which is in fact wrong. You need full cut-off to make the loco move (75, unless it's wet, snowy, etc., then 60-65 is more appropriate), and then you can go down slightly as you speed up. At 5 mph, I'd probably use 60-65. Now of course 25 shouldn't cause a derailment, but this is TSW, where weird things happen, especially when it comes to physics. The suggested 25 is like driving a manual car, and you want your car to start moving in gear 4. Not an easy task, you'll rev up the engine, which will probably stall (unless you're really good at handling the clutch).
I tried that, and for me it didn't work. The only way that I was able to complete the run is by doing what I have shown above.
