I know this will take time to build but i think this be a good route for TSW the route begins at Paddington then goes along the Great Western Mainline to Bristol Temple Meads or via Berks & Hants Line to Taunton but you can get to Taunton via Bristol as well. From Taunton you head toward Exeter St Davids going through Whiteball Tunnel built by the famous Engineer Isambard Kingdom Brunel. From Exeter you travel down past the famous Seawall at Dawlish also built by Brunel. Then you travel through the South Devon Banks to Plymouth. After Plymouth you go across from Devon into Cornwall via the Royal Albert Bridge also built by Brunel. after you pass St Austell station you pass Burngullow where China Clay Freight trains come and go. soon you will arrive at your final destination at Penzance right next to the Coast. Trains on this route are Class 43 HST, Class 387, Class 800, Class 166, class 220/221 Voyager, Class 153, Class 150/1, Class 150/2, Class 158, Class 159, Class 143, Class 66, Class 70, Class 57 on Sleeper Services.