Sarah Siddons Gauges

<guess; until I can find my pictures>

1. slave gauges for the reservoirs

2. repeaters of the duplex gauge

If I can find my slightly bigger pictures of that area then I'll have another go. FWIW ISTR that they are much more recent gauges, so

3. (bearing in mind its time as a test loco) slave repeaters giving triple valve chamber pressure (can't remember off hand if SS is QSLP triples or not).

Enlarging the picture a lot, I see the two gauges are piped with nylon pipe, so although old, they are not original! A long time since I worked on the loco but I expect it may be brake cylinder pressure for each bogie. The loco has a separate distributor valve and auxiliary reservoir for each bogie.
There's quite a bit of non-original but old equipment.

Thanks guy's, it would be useful to know when these were fitted. Also, the present day Met 12 has an air brake control fitted, is there any gauges in the cab for indication of this.

Thanks again.

Thanks Roy,
More recently, was she not fitted with air barkes to work with air brake stock as she does at the moment. If so there must be some form of pressure indication for this.

Would she actually be able to run with the remaining Dreadnoughts/Ashbury stock now then?

It's been a long time since I was trained on the Met electric locos and the T stock, ESL118A&B. 1973 to be precise!

Dual brake technology has been around an awful long time. the LBSCR Terriers were dual braked as the LBSCR used air brakes, the rest of the railways, vacuum brakes. The KESR Terriers have air brake on the loco, and vac brake for the train. The IoW Terriers only have the air brake as the Island railways used air brakes.

Similarly, the Met locos were dual braked. I remember two brake valves in the cab of John Hampden, the one i learnt on. The standard Gresham & Craven vac brake, and the standard (?) Westinghouse brake valve.

Remember Sarah Siddons was a brake test loco, it used to say so on the side, so would have had loads of additional fittings which were nothing to do with the original equipment.

From memory, you would have had the usual Westinghouse duplex gauge, and a vacuum train pipe gauge.

I suggest to get things "right", you look at the other surviving loco in the museum!

As for the technical operation of the brakes, it depends whether the loco is air over vacuum or vacuum over air! On air over vacuum, like the Terriers and Met locos, the air brake works on the loco and a valve reduces the vac for the train. Humm you say, as some steam locos have a steam brake. They all work in a similar way, the valves cause a drop in the train line air or vacuum to apply the train brakes regardless.

The only time this doesn't apply is when the loco is fitted with an independant loco brake, such as BR diesels which have a separate loco brake; on those, when the vac or air for the train is reduced, the loco brake still applies. Use of the loco brake will not apply the train brake.

Can't help with the digital speedo, too modern for me!! Back to Sarah Siddons, she was dual fitted in Met and LT days, you can tell by the air pipes on the ends of the loco. ISTR the duplex gauge for the air brake was on the left side, in the same sort of place it was on most other stock of that era.

The Ashburys were vacuum braked for working with steam locos. The GCR and BR stuff in that area was not generally air braked. I suspect the Dreadnoughts were vac braked only, again to run with steam locos.

To answer MRFS42, it is perfectly possible to work single and double pipe air braked stock together, providing you only use the train pipe. The main reservoir pipe would not be much use on a single pipe vehicle. Also, you can mix distributors and triple valve stock, as long as the driver is aware. you only get 3 brake applications with the triple valve, and needs a special driving technique! Not for the faint hearted.

The purpose of the main res on the 2 pipe system is to recharge the distributors quickly. the main res on LT stock was to operate the doors, control equipment and EP brake; LT stock was all single pipe Westinghouse air brake.