Somehow I'm in doubt this is real. I mean the Class 50 is somewhat iconic and it should find its way into the game, but a bit more Infos (if you have them) would be nice. The colours look pretty off (actually I'm not aware of a slightly violet br sceme, but also not an expert on British rail stuff) The 2 new routes coming for TSW3 are AC Electric routes, so this wouldn't fit either. And it's looking like a WIP route in the Backround, so it surely isn't just a loco dlc.
Old post... this was an "Im trying to use the graphics software and thought I'd give this a go" type thing. The loco is a direct import from TSC but isn't "coming to the game" any time soon