One of the more common complaints about TSW2 is that the HUD accelerometer is almost useless, because you can't really read anything from that big ball. But then SKA came out, and in the 423 (only) the ball changes color, blue/green/yellow depending on whether it's detecting positive, negative or no g's. This is a HUGE improvement. That accelerometer is useful! However, to my knowledge that very clever mod has not been applied to any other locos, not even the 423's stablemate the 403, or later releases like the LGV, 465 or reworked 52. Surely this can't be that difficult to do as locos/routes are revisited?
I believe that's because the HUD is also locomotive dependant, so instead of being a core game element, every train has it's own. I still find it a pretty weird way of doing things, but well, their decision. But I don't know, I still preferred the original TSWs accelerometer. The simple line was easier to read than a ball. Sure, a color changing ball makes it easier to read, but looks really stupid in my opinion. Line worked better. Though I never really look at the accelerometer, I don't even see the point of it. You're better off looking at your speed, on that you see if it increases or decreases anyway.