Unwanted Loco Labels?

For some reason this label has started appearing on some on my trains, on different routes, and I’ve no idea why.

Presumably some option has somehow got checked somewhere, but don’t know what.

How can I get rid of these label? Thanks!

 

If I remember correctly, it's one of the function keys (f1 - f10) and is a toggle switch.

 

Thanks, you could be right, as I was trying to get rid of the HUD to operate the controls. Will experiment and see if I can identify.

 

F6 - Display Destination Labels. These show the names of trains and locations relevant to the current scenario.

F7 - Display Rail Vehicle Numbers. This displays the unique numbers in a bubble above each vehicle. Note - this option requires the Display Destination Labels function to be active.

 

F6 and F7

 

HUD is F3 & F4 btw

F3 - Toggle Minimal HUD. This toggles the Driver's overlay between Off and the minimal HUD.
F4 - Toggle Full HUD. This toggles the Driver's overlay between Off and the full HUD.

 

That's good to know, thanks.