The 10A Allocation

Sorry, but if that is the case it is a very strange decision and will likely prevent it's return to Fort William, barring some miracle (where it has earnt NELPG a lot of £).

 

A lot of 'unique' locos have now been fitted with air brakes without huge detriment, just look at the LSL stable.
If you wish to run your locomotive on the mainline they can no longer be considered a museum piece, compromises have to be made in order to fit in with the modern railway - but the flip side is you get to continue to see what steam locos were properly built to do. Many loco owners have managed this delicate balance wonderfully since the owners of Clan Line 30 odd years ago realised you needed to adapt or die.
A retreat back to preserved lines would be a massive shame for the K1 which has made the West Highlands it's home.
I agree with ETRMS, but that is never going to reach the West Highlands and is a world away from air braking.

 

If you look at the current level of activity re steam on the main line and assume the level is stable, how many locos do you need to fulfill the programme? My back of envelope sum comes out at around fifteen allowing for a safety margin. Given a ten year cycle, one or two a year might get rotated in and out. That implies that quite a few old faithfuls will be off the main line charters for quite a while, air braked or not.

 

To be accurate, there are only three locos that have been converted or built with to air braking, the Duchess, FS an and Tornado. The others have been fitted with an air pump and a combined brake valve, usually from a scrapped diesel, to work the whole braking system.
In the case of Clan Line and soon to be Eddystone it means the loco is steam braked, the tender vacuum and the train air. In other words it’s all reversible if any of the engines currently working on the mainline end up on a heritage railway full time.

 

It’s only a quirk of fate that the railways of Britain and its Empire chose the Automatic Vacuum Brake and not the Automatic Air Brake in the 1860s.

USA, the Americas & Europe chose the AAB. Only the LBSCR in Britain chose AAB, which converted to AVB. And the Isle of Wight, etc.

If the railways of Britain had standardised on the AAB from the outset, nobody would have to worry about the opinions of people who want steam locos to look like they did in the 1950s & 60s when they were boys. Expecting the air compressor to be hidden underneath.

 

Only the LBSCR? So all those GER, LCDR, NER, Caledonian, Rhymney and other locos running round with air pumps and air brake hoses were just doing it for fun?

(And the LBSCR didn't convert to vacuum brakes, though some locos became dual fitted for reasons of flexibility in braked stock, just as some LSWR locos had air brakes fitted to assist with working particularly in the Portsmouth area where both types of stock were common).

As for "Railways of our empire" using vacuum brakes - New Zealand was part of the empire, but adopted the Westinghouse air brake from very early in its railway history.

You can't rely on ChatGPT to get everything right - you have to do some original research sometimes

Tom

 

I am willing to bet there are very few locos in "original condition" and none with all the parts they have left the factory with. "As retired from BR service" perhaps.

The Met is a special case as usual, but lots of air-brakes there

 

But for sound engineering reasons at the time, they didn’t choose the air brake, so actually it’s fair enough to be concerned by the resulting changes of adding them now.

 

I don’t think it was for sound engineering reasons, the air brake is clearly superior. I think some may have looked at the cost others may have been too mean or thought it unpatriotic to pay royalties to a foreign company, Westinghouse. Presumably some like the GE chose the single pipe system for simplicity or cost saving, not as safe as the two pipe arrangement at constantly applying and releasing the brake could exhaust the system ending up with no brake at all.

 

My understanding was that, with the available skills and materials, the air brake was not straightforward and its long term advantages harder to see.

That needs to be understood in the light of the railways of the time resisting imposition of automatic brakes at all, and continuing to run unbraked goods trains for many decades later.

 

So what are the disadvantages (engineering-wise (the originality argument has been done to death)) of fitting airbrake kit?

 

To add to the list GNSR and Isle of Wight; also the Midland, GSWR, and North British originally chose the air brake but then converted to vacuum, though the North British was delayed by the first war and still in the process in 1923. The air braked train in the Newark Brake Trial was Midland.

 

Did the IoW company (which one btw?) have a choice in the matter? I thought they were stuck with whatever they could find 2nd hand...

 

I believe the FYNR used the vacuum brake; the other companies were exclusively vac braked.

When the SR took over, the decision was made to standardise on air brakes. Where necessary, rolling stock bought in by the SR was converted to air brakes, for example the Adams O2s (which by design were steam-braked locos with vacuum gear for trains) were converted to have equipment for running air-braked trains.

Tom

 

I have always thought that the SECR plumping for VAB (as per SER) rather than WAB (as per the Chatham) was the great lost opportunity. Hindsight goggles on, of course. Brake compatibility with train ferry traffic, the Brighton at Grouping and the LSWR Electrics would, no doubt, pushed the Southern towards WAB. (Incidentally, how did a VAB fitted steam loco rescue a failed WAB fitted juice unit?)
Pat

 

One advantage of being all air-braked is that the tender can be braked to its actual weight. Its a standard feature of air braked stock (compulsory on modern wagons) for the brake force to vary with the weight. With vacuum the braking has to be set up for the empty condition, otherwise the tender will be overbraked and the wheels will be like threepenny bits in no time at all. Taking a Urie 5,000 gallon tender (extreme example, I know) Empty weight 30T 03cwt; fully laden 57T 13cwt.
Pat

 

At the time the 2 pipe wouldn’t have been available and it remains a more expensive system which for example is not used in US freight trains even now. @35B has covered the other considerations. The WAB is more complex to build, maintain and to convert existing vehicles to have. But I think that the key consideration would have been the simplicity of extracting air from the train pipe if you have a steam engine….no moving parts v a complex reciprocating pump. Given train weights and speeds in the UK at the time, the stronger brake wouldn’t have been, and wasn’t to most sufficient to overcome the simplicity.