Train Sim World 2

There's a service 2nd from bottom on the list which is perfect for grinding this. It's 23:40 - Empty to Depot.

You'll need to wait for the signal to go yellow, then you can go full throttle through the wash and stop at the siding. You can complete the service in just under 3 minutes which will speed this achievement up a lot.

Then you can just replay the service over and over from the service end screen. It will count towards the progress.