Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Sept 22, 2011 6:39:02 GMT
Do A stock cabs have an ammeter to help driver not to overload the motors?
|
|
roythebus
Pleased to say the restoration of BEA coach MLL738 is as complete as it can be, now restoring MLL721
Posts: 1,275
|
Post by roythebus on Sept 22, 2011 7:16:10 GMT
AFAIK no Underground stock has an ammeter. there is no need for it. If there is an overload, almost impossible on tube stock, the overloads will trip out. On the traditional stock, like older buses, LT put the bare minimum of informative devices in the cab for the driver to worry about, less for them to fail the unit on! I think the only LT stuff with an ammeter were the Met locos!
The 4 position controller on SR stock and their camshaft control gear is almost identical to that on LT. On the SR stock, weak field position 4 will only put the motors into weak field once they have reached the full parallel. It has the same effect as the flag on A stock!
Me thinking of the driver having to open a cupboard to raise the flag, I was thinking of R stock where the flag was in the destination light cupboard!
The flag is positioned away from the driver's "easy reach" to make raising the flag a deliberate move.
My memory is fading a bit, as it's 1973 when I trained on A stock, and the Met locos! And 1979 when I learnt the SR stock.
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Sept 22, 2011 8:57:48 GMT
Thanks for your reply Roy. So really the met stock could have been designed without the weak field switch with a system that allowed weak field to be selected once full parallel and a 4th notch had been selected.
I think back in those days no EMUs had ammeters in the driver cabs. Instrumentation was very basic. I know the SR EMUs had an ammeter in the guards van.
Nowadays it seems very different with computer screens giving the driver access to all sorts of train data.
|
|
roythebus
Pleased to say the restoration of BEA coach MLL738 is as complete as it can be, now restoring MLL721
Posts: 1,275
|
Post by roythebus on Sept 22, 2011 20:51:20 GMT
I don't think so. what use would an ammeter be for the guard? you're not mixing that up with the train pipe brake pressure gauge are you?
Yes, A stock could have been made with a 4 position controller, but LT didn't want trains exceeding the speed limit in tunnel sections. Hence the weak field selection is a deliberate action.
|
|
