Do you mean when you're trying to buy the end powercar as a standalone unit, and not a multiple unit? The easiest way would be to add a multiple unit lua file, that just has the endcar reversed. It'd be tougher to reverse the actual model in the mdl file because the car length isn't symmetrical.

I've noticed this too. Here's the FIX for anyone who wants it...

Go to the Acela Express mod folder through this path...

(YOUR DRIVE:)\Steam\SteamApps\workshop\content\1066780

Take the Mod path to the Acela_Express.lua file as follows:

2009942692\res\config\multiple_unit\usa

Edit the Acela_Express.lua file (I use notepad ++)

In the vehicles = section go down to the last vehicle (it's the only one named powercar2020.mdl)

Where it says forward = false, change it to forward = true

Save the file and restart the game. Go to purchase the Acela Express and the rear car will be facing the correct direction.

Hope this helps!