Guard's handbrake query?

Remembering a comment on this forum from 2 or 3 years ago, I believe there is at least one heritage railway that has modified a handbrake which when screwed down opens a valve to destroy the vacuum of an automatic brake.

I need to identify any UK heritage railways that have done this. Does your railway meet this criteria please?

Chris

 

The NNR has a dump valve fitted to some of their MK1 brake vehicles and the LNER pigeon van as well I think.
From what I can remember if the handbrake had more than a couple of turns from the off position then the valve would be open and a vacuum couldn't be create.
The valves themselves were originally from a 47.

If you need them PM me for contact details.

 

Welshpool and Llanfair does and I understand the Ffestiniog does also.

 

Most SVR passenger brake vehicles have been fitted with a valve operated by the guards handbrake which, when applied, prevents train pipe vacuum being created above 15".

The objective of this is to alert drivers to the fact that a handbrake remains applied preventing movement & in particular avoiding the risk of wheel flats on brake vehicles where the handbrake has not been properly released.

Slang term for this item amongst staff is the "idiot valve"!

 

The NYMR have an SVR style device fitted to the GW Saloon 80974. It has the same effect as if the communication cord had been pulled - unable to achieve more than about 14" of vacuum. Hence, the loco can attach to the set and start creating vacuum with the hand brake on but can't obtain full vacuum until it is removed. No safety issue as the hand brake is only wound off after the loco is attached.

Steven

 

None of the lines I've worked on have these, but they all run short sets, where one handbrake is enough extra drag to be obvious to the driver.

If it has slack in it, it's going to snatch whichever brake you take off last.

 

I think half the reason the NNR system doesn't allow any vacuum to be created is that with a bigger diesel such as a 37 or large steam loco such as the WD the set could still be dragged along with the handbrake partially applied or stock with dragging brakes.

Before splitting the loco from the stock the handbrake is applied as are the train brakes, the stations are pretty much on the level as well.