Hi I think St Pancras to Lille via the channel tunnel would be a great route for relatively low development costs comparative to the mileage involved. Lift HS1 from SEHS from St Pancras to Ashford Ashford to channel tunnel (about 30ish miles) Channel tunnel (31 miles) - little scenery as its all in a tunnel Channel tunnel to Lille (about 50 miles) Total about 160 miles If Eurostar licencing is possible then there's 2 core gameplay areas available already. 395 to Ashford (395 lifted from SEHS) Eurostar St Pancras to Lille Le shuttle would potentially add the 3rd with gameplay I don't know what the situation is with SNCF but they could add Calais to Lille TGV Even DB could get in on the act depending on timetable developments etc Trains 395 from SEHS Eurostar 320 is based on the ICE3
Few issues here. It duplicates a large part of the existing route. Driving through the HS1 tunnel sections is pretty boring and once the novelty wears off the Chunnel will just be more of the same but longer. Eurostar are apparently one of the operators not prepared to agree a licence deal for a game. SNCF also apparently not prepared to see their infrastructure or trains in any further TSW products.
For the infrastructures, it's in the scope of SNCF Réseau (former RFF). Anyway, you just have to arrange things as in the WCML in regard to LNWR. You don't need a licence, do you ? It's an artistic depiction of the world.
