The black and white dial. I've seen them a few times and always wondered.
Thanks!
So what's the white round thing then?
@sutty What class of loco/unit is the picture of the cab panel taken from?
It looks like a networker, to me but I'm not sure
465. (img attached)
The metal button is the AWS reset. This one protrudes a bit more than some and has a nice bright green(ish) surround.
I'd say the surround is more yellow on the 465s. The 365s are (or were) the same, but don't have the yellow (or bright green) surround.
Found It! It's a class 332 Heathrow Express cab. That white thing must be the AWS reset I can't see any other switch that would be suitable
I think that's possibly where you found the original photo:
http://1.bp.blogspot.com/_MOVYEYFn5Vc/S8hZz18HMhI/AAAAAAAAABs/b_xMvNOWiO0/s1600/DSCF0054.jpg