PlayStation Marseille Return Scenario- Tvm430 Is Disabled When I Load The Save.

I've attempted to complete this scenario several times now, but have been unable to.

Firstly, I had a problem when I completed the first stage of the scenario, then saved and quit. When I reopened the save and departed Marseille back to Avignon, everything seemed fine, but for whatever reason I couldn't change power modes when I needed to. I didn't do anything different from what I usually do, it simply didn't work. The changeover worked when I was heading towards Marseille, so I assumed it was a bug.

So I replayed the first section of the scenario again, and then turned around at Marseille for the return portion of the trip back to Avignon. This time changing power modes towards Avignon worked fine, so I saved the game and quit. It's a long scenario and I have a bad attention span, so I'd rather not do both journeys in one sitting.

But if it's not one problem it's another, now when reloading the save for whatever reason the TVM430 system isn't enabled. Checking the panel behind the driver's seat reveals that it is isolated, and switching it back to normal doesn't appear to do anything, probably because the train is in motion. I've tried reloading the save several times now but to no avail. Obviously I don't wanna play without it for the sake of realism, and it would probably be needlessly difficult.

Has this happened to anyone else before? The only solution I can think of is to play the whole scenario in one sitting, and I've already explained why I'd rather not do that.

Thanks for reading!