Steam Brake Questions

The Taff Vale Tank at the KWVR has a steam brake. The loco is also fitted with a Dreadnought ejector to operate vacuum brakes on the train. There is no provision for the automatic vacuum brake to control the independent locomotive brake. I presume this was a common arrangement on older locomotives. Can anyone confirm this?

The MR (design later used by the LMS) and LNWR I believe used mechanical arrangements for working the steam brake and vacuum brake together. The GWR had an arrangement with the "setter cylinder" to operate the steam brake with the vacuum brake.

When did other companies start to use steam brakes that could be controlled by the vacuum brake? (I have seen brochures from both Gresham & Craven and Davis & Metcalfe from the 1920s that illustrate vacuum control of the steam brake - were there earlier versions or was this the start date of such arrangements?)

Going back to the Taff Vale tank, it has a duplex gauge. The one hand obviously shows the train pipe vacuum, but if there is neither a vacuum brake, nor any kind of vacuum control for the steam brake, then what does the "vacuum reservoir" side of the gauge measure?

 

You’d maybe be better off asking on FB - Unofficial Keighley & Worth Valley Railway.


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Is the Dreadnought a Preservation fit.... isnt it ex-NCB i doubt it would have had Vac operational then... was it fitted with a Swindon boiler at any time

 

The requirement for the brake to operate throughout the train came in with the Regulation of Railways Act 1889. If the loco was used on vacuum braked passenger trains it would have had to have a combination brake whereby a reduction in vacuum caused the steam brake to be applied. That went out with the Railway Safety (Miscellaneous Provisions) Regulations 1997 which simply stated that "The operator of a vehicle shall ensure that a suitable and sufficient braking system is provided and maintained for that vehicle and, where the vehicle is part of a train of vehicles, for that train of vehicles." This was largely worded to allow ex industrial locomotives on heritage railways to have a simpler form of continuous brake, something that had been done for many years and which, although illegal at the time, the Railway Inspectorate (Major Olver initially) had turned a blind eye to. As Ianh has said, the loco came out of NCB service and the original combination braking system would have been replaced by a conventional steam brake.

 

85/426 probably received GWR safety valves (and cover) but never a GWR boiler. According to RCTS it had a very major overhaul at Vickers not long after the grouping. I reckon photos on line show that the GW safety valves were lost during the industrial career.

 

As I understand it, the vac brake works on the basis of the pressure differential between above and below the piston. When the air is removed (ie the brake is blown off) these are equal and the brake comes off. As the driver admits air the vacuum on one side reduces and the pressure differential applies the brake.

The reservoir part of the gauge represents the vac level in the section where the pressure does not drop. Having a reservoir connected to this part of the system means that any small leak will be spread over a larger area, minimizing the impact.

That said, I only sign air brakes, so I may be wrong

 

Major Oliver was quite up-front about not enforcing it in some cases. Foxfield has an official letter somewhere letting us off the requirement until such time as we got around to fitting the engines with combination brakes, with I think the fairly clear expectation that we never would.

 

There were examples where in was not enforced long ago. When pulling air braked trains, the Highland Railway Castle class used a Westinghouse pump and brake valve, there was no link between this and the vacuum brake system on the locomotive. So the driver had a completely independent brake system in that case. These locos were put into service in the early 1900s, so not very long after the law above came into force.

 

Your description is correct. Hence my question. The locomotive itself has only a steam brake. No vacuum brake therefore no vacuum reservoir above any piston. The only vacuum brake equipment it has is a combination ejector for the train.

 

The vacuum reservoir side of the gauge will in this case be displaying the amount of vacuum in the side of the system where it is not affected by the driver braking (sorry I do not know the technical term)

 

I don’t know but guessing it is most likely that the chamber side of the gauge isn’t connected to anything if there is no combination brake valve on the loco. It certainly won’t be connected to a chamber on any of the cylinders on the train.
Another possibility that has just occurred to me is that the Worth Valley may have cobbled together a system of their own which applies the steam brake when the train pipe vacuum is dropped. I know that they tried to do this on another industrial loco using a shuttle valve. The chamber vacuum would be used to provide a vacuum differential to operate the shuttle valve.

 

Just a thought - it may have a duplex gauge, but are both sides connected? Or do you only get a reading of the pressure in the train pipe, and no reading for the chamber side? In other words, could they have used a duplex gauge because that is what they had available, but only one side is reading?

The reason for wondering is that the braking seems somewhat similar to Captain Baxter on the Bluebell after its most recent overhaul. That loco only has a hand brake. A vacuum ejector was fitted which could create a vacuum in in a train, and there was a brake application valve. The vac gauge on the loco just had a single needle; and when braking a train, the loco was unbraked weight in the total.

Tom

 

We are all guessing about this when a quick look at the loco would probably provide a definitive answer.

 

To add to your descriptions of the MR/LNWR/GWR braking arrangements, here is a quote from Tuplin's book on Great Central steam, referring to the Robinson locomotives:

"The brakes on engine and tender were worked by steam and all classes were fitted with an ejector for working vacuum brakes on the train. The steam brake could be applied independently of the vacuum brake, but a piston connected to the steam brake handle caused that brake to be applied whenever the vacuum brake was sufficiently heavily applied."

I cannot comment on the technical details, but do find it interesting how many variations of braking systems were used on British railways in the steam era. As with so many other design features, different railways and different engineers went off in their own directions. Train braking might be either air-operated or vacuum-operated, while the engine and tender could be braked by air, vacuum or steam (not to mention some small shunters with only hand-brake).

Among the more complex arrangements were on the WD 2-8-0s & 2-10-0s. When originally built during WW2, they were equipped with both train air brakes and train vacuum brakes, but used steam brakes for the engine and tender. How many handles and gauges were needed to operate all 3 sets of brakes?

 

To avoid patent infringement?

Have a look on the footplate of 600 Gordon at Highley!

 

I think some of the LSWR “Jubilee” class must have been similar. Normal set up would have been a steam brake on the loco and vacuum for the train, but a number were additionally equipped with air brakes to simplify station working at Portsmouth where they would come into contact with (and might need to shunt) LBSCR air-braked stock.

Tom

 

There is - or lately was - something like the WD tender locomotives when Clan Line was running with air braked stock:

Steam brake, on the locomotive
Vacuum brake, on the tender
Air brake, on the carriages

I would not expect but there could be, a pressure gauge on the steam brake and I wonder wether or not it could work both one pipe and two pipe air.

 

Indeed. 555 worked Queen Victoria's Funeral Train from Gosport to Fareham. Brighton men always said that South Western men couldn't work Westinghouse properly; sadly, they were probably right if the Hampton Court episode in 1900 is an example.
BoT_HamptonCourt1900.pdf (railwaysarchive.co.uk)
Pat

 

That seems even more complex than the WD situation, in that all 3 braking systems need to operate at the same time. I guess that the Clan Line team judged that it would be even more complicated and costly to have changed the loco braking system away from the Southern speciality of engine steam brake plus tender vacuum brake. Some of the SR U-class 2-6-0s had dual train braking pre-1939, possibly with a similar arrangement to Clan Line.

Thanks for posting the link to the report on the Hampton Court mishap - an interesting read.

Although the engine is only identified as "four-coupled", it seems likely to have been one of the dual-fitted Adams "Jubilee" 0-4-2s mentioned above by @Jamessquared. The report indicates that the engine had power-braking on its coupled wheels, but apparently only hand-brake for the tender wheels. There is no adverse comment from the Inspecting Officer, so that must presumably still have been common practice in 1900 and regarded as compliant with the 1889 Act. I believe that by the time of the 1923 Grouping, all main-line tender locos had some from of power-braking on the tender wheels - even slow goods engines with only steam brake.

The 1900 report describes use of hand-brakes to help control the moving train, not just by the fireman operating the tender hand-brake but also by the guards using the hand-brakes in their vans. Perhaps staff at the time were not fully trusting of the newfangled air and vacuum carriage brakes?

The Inspecting Officer concludes that the buffer-stop collision occurred because of the driver's ineffective use of the Wsstinghouse brake, but is a little vague as to exactly what he thinks the driver did wrong. The driver had used the brake to slow the train on approach to the station, but then released it. Had the carriage air reservoirs had time to fully recharge (via the single train air pipe) before he applied the air brake again? There was evidence that some of the carriage brake blocks were gripping only loosely after the accident. It was also raining at the time of the incident, so wet rails might have been an aggravating factor in causing the driver to misjudge the required stopping distance. All speculative of course, but one hopes that Dugald Drummond was not too severe with the driver.

 

Possibly, but the report's a bit vague, mentioning Steam, Westinghouse and handbrake. It could simply be saying that the handbrake worked on the tender only, standard practice up to the end of steam in 1968.

This seems to have been fairly common at the time: it was LNWR policy and written down from higher up that the train should be checked by using the handbrakes and the power brakes were for emergency use only.