One thing that's disappointed me on both train sim worlds is that there's maps for all over the U.K. Somerset, London, ECML, Teeside and the latest being Scotland yet there's not been one map on the West Coast Mainline which is the busiest mainline for freight trains, has numerous big depots Crewe having 5 depots right next to each other. There's also West Coast Railway and Locomotive Service Limited based along the WCML so plenty of diesel, electic and steam to do charters with. Maybe you could maps in sections as I know you wouldn't be able to make a map the full way so London Euston to Crewe, Crewe to Carlisle and Carlisle to Edinburgh. Note the Crewe to Carlisle could involve the Settle & Carlisle Line going via Ribbleshead etc as West Coast Railway and Locomotive Service Limited both do a lot of charters that way. At the end of the day I thick it's time the WCML got a look in to the game
I think for the Southern WCML I think a Class 350 would be needed, as the most common passenger trains out of Euston are Class 390s and class 350s.