Raildriver has been supported in tsw for some time already. It's not perfect but you would be able to use it in tsw
Well I got it at lunchtime, did the calibration and tried it on a couple of engines, seems to work OK but I did have to use te keyboard at one stage as it didn't recognise the throttle, but later it did. Sometimes I think I've done everything and the engine won't move, nothing to tell me why, I go clicking on things hoping that was it, I've had to exite a couple of times and go on another route/engine. Col.
I've noticed on some engines if I select the 'Forward' on the RD it does nothing in the actual cab, I still have to do it with the mouse, also the throttle doesn't always work in some cabs. Side issue, what are the other blue buttons for on the bottom of the RD?
If you go to the calibration screen it will show what the 2 rows of blue buttons do for the 3 locos showing on that screen (hover over the orange buttons to see what each one does), in TSW2/3 that info was displayed for all locos in the game but that info has vanished with TSW4.