34039 Boscastle WC class

This locomotive has been mentioned at times in the large Bulleid thread elsewhere here but, as it could be back in steam in the next couple of years, I think a dedicated update thread would be useful.
This locomotive came to the Great Central Railway in 1973 - the first Main Line locomotive to arrive. It was restored from "Barry condition" over the next twenty years and ran (mainly) on the GC until withdrawn around 2000 with firebox problems. It was stripped down and the bottom end has now been largely refurbished and re-assembled. The boiler was sent away to South Devon a year ago and it now has a new inner firebox with new thermic syphons. Much of the outer firebox is also new. It is expected that the boiler will return around April/May time.
The tender frame and wheelsets are being refurbished and I believe, a new tank is being made (- the old one had been out on hire but had become increasingly "leaky").

 

Thanks for the update, Phil.
This was Boscastle on arrival at the GCR from Barry. The kid by the buffers is me. Of the two, I think 34039 is currently in better condition....

51499556_10215960745045830_6792040958109155328_o by Raimondo posted Feb 23, 2019 at 12:30 PM

 

Excellent photo Raimondo, many thanks. This was the boiler move to the SDRE last year...A tight squeeze!

 

This is the old tender tank, still at the back of Loughborough Loco Shed.

 

Well she was never in good condition...

AFAIK there was a lot of restoration work to get her from Barry condition to running, and the amount of work and the time required to do it was originally severely underestimated, "she'll be ready soon..." - "soon" transpiring to be about 3 times as long as the original estimate. Then when she did run, she ran for only a short time before having problems, and progress speed on fixing these problems seems to be about the same as the original restoration.

I assume the slow progress is due to the difficulty of the work rather than slovenliness by the restorers,

However, I suspect she is cursed and the gods don't want her to run...

 

It is true that the original restoration cost/time was severely underestimated......weren't they all! Many on here will remember that inflation in the 70's was horrendous in its effects. Also the priority on the GCR during those times was survival and prioritising the running fleet (2 or 3!).
The work being done this time is far more extensive and to a very high quality so I hope the Gods will shine on her.... in a year or two!

 

The original owner (still involved) James Tawse sunk a huge amount of his own money into just keeping the GCR afloat in the early days, so it’s no wonder he ran out of it before finishing Boscastle, and the restoration dragged on and on, the first time around.

I’m not sure it’s fair to say it wasn’t done to a high standard though; the loco would surely have seen out its first 10 year ticket but for the usual Bulleid steel firebox woes, and isn’t the only Bulleid to have been withdrawn early in preservation with this issue.


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Do the firebox issues that befall Bulleid pacifics occur due simply to the age of the locomotives / boilers or is this a design weakness that needed regular firebox replacement when locos were in service with Southern and BR?
Also, would a copper replacement firebox give more lasting "fix" than replacing steel with steel, given that this could even be possible?

 

In their paper on experience with Bulleid pacific steel fireboxes published in 1958, Burrows & Wallace came to the conclusion that the life of these fireboxes would be between 15-17 years but would require significant repairs in that period. Steel fireboxes are generally easier to patch than copper ones. A fundamental difference between a copper firebox and a steel one is that, even when not in service, the steel box is going to be the subject of corrosion, albeit probably at a slower rate than when in service, so time in Barry would be part of that life expectancy.
The boilers were designed for a steel firebox. Substituting a copper firebox would essentially entail designing a new boiler with a conventional foundation ring. Not impossible, but not really an option.

 

I will be shot down by some but is there a case for a simpler firebox without thermal siphons for locos that will only operate on heritage railways? I realise that the whole stay pattern and other factors will need to be allowed for but the siphon's 'shoulders' seem to be a source of problems.

 

You’d be into a lot of redesign work, not least supporting the firebox crown I believe.

I’ve often wondered though whether, for heritage line use, a reduction in working pressure to, say, 220psi would be beneficial, with minimal impact on performance but reduced water side temperatures.

Purely as a hunch, but I’ve sometimes wondered whether the wartime and immediate post war steels were of a consistent quality, which might lead to subsequent problems.

Tom

 

Boscastle in the early 70's

 

My thoughts are more along the lines of older steels had more impurities in them and were actually better in terms of corrosion. You can see this in many boilers where the bottom part of the outer wrapper has been replaced. The new steel has often corroded significantly more than the older steel when next exposed.

 

Boilers in the early days of preservation suffered from a lack of water treatment to reduce scale formation and both acidic & oxygen (free radical) corrosion.

Water treatment by addition of chemicals alone or softening & reverse osmosis plus chemicals means that in these more enlightened times some boilers are running for 10 years between overhauls and only needing retuning and a few stays renewed.
In some ways, poor quality coal now affects boilers by damaging stay heads and lap edges in the firebox, in worse ways than what is going on in the water.

 

The suggestion of replacing a steel firebox in a Bullied Pacific by copper overlooks the reason that they were fitted with steel in the first place. As I understand it you cannot build a copper box with thermic syphons, which in themselves are an integral part of the firebox design. To do away with the syphons would involve a radical design of the boiler and I doubt anyone would want to go there these days. But I'm not an engineer and I'm happy to be told I'm wrong if that is the case

Peter

 

You're far from wrong, Peter. One of many considerations along with foundation ring, firehole door ring, stay spacing and a few other things, all of which effectively mean a new boiler. You might get away with the barrel itself remaining unchanged.

 

I might be wrong, but I understood that one of the main reasons for originally selecting steel on the Bulleid Pacifics was the 280psi design pressure, which was beyond the limits for a copper firebox. Use of steel also allowed greater use of welding in the construction, which saved weight (and material).

As you and others have pointed out, changing now to copper would be a fundamental redesign, to all intents and purposes a new boiler. By way of contrast, there is now considerable experience, and all the right forming blocks for the presses, to make entirely new steel fire boxes for Bulleid Pacifics A brand new steel firebox of known design is going to be way cheaper than a brand new copper box of unknown design with all the attendant design and compliance work.

Tom

 

Foundation Ring? On a West Country?

 

I think Steve is referring to the lack of a foundation ring as one of the many considerations to be taken into account.

 

Bulleid doesn't actually say that directly in his paper and this was one of several factors. What he said was:

"The use of steel would effect a large reduction in weight as compared with copper, which in the case under consideration would be at least 1 ½ tons. During the war, too, anything that would reduce the use of copper was desirable. The use of steel fireboxes on recent French locomotives with 280 lb. per sq. in. pressure and over had been satisfactory and, in fact, the author found the French engineers convinced that for such pressures steel fireboxes must be used. The successful introduction of the Nicholson thermic syphon had provided a reliable means of improving the boiler circulation whilst, at the same time, giving added security against over-heating of the crownplate. It seemed reasonable to expect good results from steel fireboxes provided that care was taken in the design to allow for the differences between steel and copper, and also that all reasonable precautions were taken to ensure that the fireboxes were treated with proper care in service. It was therefore decided to use steel fireboxes on these locomotives."

BR of course found through testing at Rugby that the syphons made no difference to steam raising ability (which Bulleid did not claim), but presumably Bulleid owners take the view that getting a re-design approved is more expensive than replacing the syphons.