I don't actually know but it goes from derby to Nottingham you can only go from Nottingham to Leicester not derby to Leicester you can only drive the hst from derby to Nottingham
I don't have the route, so I can't check the in-game timetable to see what's in it, but I can check the current working timetable in real life! I'm not sure what the service pattern was like during East Midlands Trains, but East Midlands Railway sometimes use their class 222s on stopping services between Nottingham and Leicester, and between Derby and Leicester. EMR have regional services using class 170/class 158 trains between Derby and Nottingham They also run those trains between Leicester and Nottingham: but they don't seem to run any regional trains between Derby and Leicester in real life: https://www.eastmidlandsrailway.co.uk/timetables
That's how it is in reality, two trains an hour between Leicester and Derby XX:06 and XX:37 departure times from Leicester, one is a fast service and the other is a stopper, both come from London and go to Sheffield.