The Class 31 has been in TS classic for many years now, and in 2018, Armstrong Powerhouse made an Enhancement Pack for this locomotive. In short, the EP is decent where the sounds, physics and included liveries are concerned, but I think it's too expensive for what you get.

(If anyone's curious, footage for this video was recorded on the following routes):
[GAD] West of England Mainline
Epping-Ongar Railway
Holyhead Breakwater Railway
Just Trains - North Norfolk Railway
Marsdonshire
North London Lines (BR / NSE)
South Wales Coastal - Bristol to Swansea
TestTrak
WCML North
WCML Over Shap
West Highland Line Extension
Weardale & Teesdale Rail Network