air brakes on narrow gauge stock

Hi,
would anybody know of a company that has perfected a ' bolt on ' system for brakes on narrow gauge rolling stock that would not have been fitted with brakes from new.

 

Talyllyn Railway Company

 

And most of the 15" gauge lines around, plus Leighton Buzzard, Alan Keef.

Depends if you want single or twin pipe. Both are very simple to "bolt on"

Craig

 

I gather that Leighton Buzzard used lorry air brake components. In this twin-line system the red (emergency) pipe/hose is pressurised all the time to charge the reserviors on the train vehicles via relay/emergency valves. If this line breaks, the brakes go on.

By pressurising the other service pipe/hose (yellow), this sends a signal to the relay/emergency valves which in turn supply air at the same pressure to the brake cylinders. Should a yellow line fracture, and provided the brake valve is still applied, air will be released from the reservior on the loco. This in turn will drain the red line thus causing the emergency valve to apply the brakes due to the difference of lowering air pressure in the red line compared with the pressure in the reserviors on the vehicles.

 

I can confirm that this is true and all parts can be purchased from a lorry auto factors for the coaches anyway. I would imagine that this is the same system that also runs on the VoR as well.
This is a development required by the stopping of production of the triple valve formerly used on underground trains. (and used on the first generation of single line air breaks witch means any available are in high demand from the railways still using the system South Tyndale, WHHR ) If you want to buy the system of the shelf Alan keef as already stated would be able to do this but you would not get the rules and processes needed to ensure safe operation. As IPR would have to be paid to the railway that created them. But you may want to contact railways direct as they may sell you the knowledge for less than Alan Keef.

 

We also use ex lorry parts for our single pipe airbrakes on the GVLR.

 

Ravenglass and Eskdale developed a single air line automatic braking system somewhere around 1977 after a meeting between steam and diesel. It used an ex lorry anti-compounding valve to do the work of the triple valve. I don't know if this system as it was then is still in use today. My engineer friends that used to work on this line have all retired now.

Regards,
John.

 

At Apedale, we use the two-pipe air system which is similar to that used at Leighton Buzzard and many others. It is sort-of becoming the de facto standard for NG - but (as they say) other systems are available.
The main advantages of the system are that it is robust, simple and the parts are cheap - because it uses lorry technology. Each vehicle is fitted with an RE - Relay Emergency - valve. The function of this is broadly analogous to a distributor for those used to "BR-type" air brake technology.
There are some subtleties in the design to make it fail safe and relatively fool proof. Firstly, the fail safe feature is provided by the permanently charged emergency line; loss of pressure in this applies the brake. Therefore, the intervehicle connectors must function such that air is NOT retained in the event of the train parting.
Secondly, the issue of interaction between the air system and any fitted parking brakes. The functionality needed is that EITHER system can apply the brakes but BOTH must be released to remove brake force.
Thirdly, the issue of double heading, dead loco moves and the like takes some thinking through.
I don't think there are any issues which haven't been solved, and the system IS reliable. I would not like to go back to driving trains on hand brakes only. A powerful air brake is a considerable confidence booster in many situation!