https://steamcdn-a.akamaihd.net/ste...st_Generation_Pack_Manual_EN.pdf?t=1512119181 This is the manual for the virgin pack and it says on page 11 that master Key is C
I assume it's interlocked with the control desk so if the reverser is in a 'running' position (engine only, forwards, reverse) or if the throttle is open then the key won't come out.
Probably why they changed it to the must less accident prone CTRL+W in later models. I used to have issues with missing A and hitting Z when I first started playing and then wondering why the trains weren't going anywhere... (for those that don't know, Z is engine off on some locos, so I was effectively killing the loco)
The Z key shutting off the engine is so stupid. Make it CTRL+Z or something so you don't do it accidentally. I don't know how many times I've gone into the free view (the one that lets you fly around wherever you want) and hit shift to move faster, but also hit Z by accident since they're right next to each other.