Okay hear me out, a TSW2 route between cheltenham spa (CNM) and Bristol Temple Meads (BRI). you could have Crosscountry class 220 and 221s or XC HSTs? GWR 158 or 150 classic sprinters. and maybe the nuclear flasks with class 68s or 37s which would run from Berkeley or bridgewater. via Gloucester. Also maybe Tampers or track machines?. I may have gone on a bit there but it is roughly the same distance as Northern trans pennines leeds to Manchester. Just my thoughts.
Tampers are a definite yes from me. Always wanted to have track maintenance machines on TSW as they normally are very common every evening and often seen out and about on Driver Training.
I like the track maintenance vehicle idea. The Class 68 and/or Class 37 with nuclear flask cars (and other freight rolling stock as well) would make for interesting services.