Is there much difference between the Class 375 and the 377 in TSW? I understand the 375 uses a different power source not sure if that's correct. I love the 377 in ECW and looking at getting SEHS which runs the 375.
In game, almost identical. There is no speed limiter, and the sliders to set the train length below the speedometer are not part of the 375. Sounds are the same as the 377.
Only difference is that the 377 has external CCTVs and a CCTV panel in the drivers cab. The 375s had older different headlights but they were upgraded to the same as the 377s in the 375/9 upgrade. In game testing, I've found the 375 to accelerate faster then the 377 even though they both use 750V DC third rail for power.
The 375s, like all early Turbostars and Electrostars, have no external CCTV, and there are also many technical differences between the classes. However, the two classes likely would be able to work in multiple if there was ever a situation where the had to. The earliest 375s are older than the 377s and, as a result, some subclasses of 375 (as well as a few early 377s) have the old three light design, which was used on all Turbostars and Electrostars until new units were built with the new design. No Turbostar or Electrostar has had their headlights upgraded. The 375/8 and /9, which is modelled in the game, have the new headlight design. Of course, the only reason the /9 is modelled is because they didn't want to model the old headlight design on the far more popular /6 and /7 subclasses used on long-distance Mainline services. In reality, the /8s and /9s are more often found on Hastings services. There are also minor technical differences between the 375s and 377s.