Tees Valley Class 37 Sound Mod v3

This mod changes some sounds on the TVL Class 37-5
The Horn is now 2 preset tones. Low -high by pressing low tone key and high-low by pressing the high tone key.
Engine sound tweak low power now results in a smooth rev insread of on/off.
Loco Bogie sounds- joints have been given a heavier tone whilst no longer being prominent in the Cab.
Flange squeal has been toned down and given more base.