Part 10 is the penultimate edition of the series and covers West Cornwall Local. Class 43 & Mk3 HST set in Intercity Swallow livery (original Valenta engined). Class 50 Hoover diesel electric locomotive in BR large logo blue.
Because it would be more than a simple re-livery. Different cab, engine type and passenger interior. Although Skyhook did do this for the HST included in MML. Also, WCL is not the best route for stretching the legs of a HST, so such would be better included should another appropriate route be produced then layered back on, or even if WCL was revisited an extended across to Plymouth, however unlikely that may be.
Even better if they had extended the route to Falmouth rather than St Austell to better fit in with the "local" theme using the Sprinter. They could have included certain St Ives services running through to Penzance as well, to make the main line look a little busier.
I would have rather they did it to Plymouth for a full route, although the St Ives branch is a nice touch.
The mainline appears dead with minimal traffic when played. 158 in Regional colours operating through services to Cardiff and beyond seems worthwhile. Would need some backdating for the 158 though but not too much work.