Nunney Castle

Good point. I suffered a failure in that manner once, traced back to a dodgy batch of Moroccan chicken from the deli opposite work. Potentially more destructive than broken stays as well...


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Cracks, yes, but not breaks.

 

Steve,

Once you've seen it and pulled out both halves of the stay from the water space, you know it happens. I don't know the ins and outs of the chemistry of the buildup of the stays - as it was the best part of 18+months ago.

Sidmouth also says that the leaks were down to this dodgey material... In my experience dealing with said dodgey material, there were no leaks as such. They hammer tested and sounded like they were fine, but when X-rayed - they came back as being broken.

Again, I'm not saying this is what is happening with Nunney, I only have my own experience with dealing with this copper.

 

Thanks for the explanation. I can accept that the stays have cracked at both ends but I'm reluctant to accept that they have actually broken although I'm perhaps being pedantic in the terminology. If they were broken in two places, you'd be extracting bits of stay when washing out the boiler.
As to what's happening with Nunney, we need further and better particulars.

 

The green signals tour of LSL included a look at 5029. LSL's Managing Director, Tony Bush, says at 26:19 in the video, that they plan to have the engine in one piece by Christmas/New Year. May we see 5029 based at Bishops Lydeard next summer?

 

That would depend on if a castle still fits the NR gauging limits, between its base at Crewe, somewhere like Paignton, Plymouth , I know that Vintage trains has operated its Castles in the west country recently But of course, no two classmates will be the same

 

Sorry, i was thinking more along the lines of things like new tyres, vs older that have had several turnings, spring hights, I'm sure that the gauging will take such things into consideration, and then theres the clearence with overhead live wires, are the hight restrictions the same regardless over the network, wither there is overhead electric lines, or not?

 

If the narration on that video is to be believed she will fit better than the rest as they are apparently restoring her with 6' 6" driving wheels, very GWS to put a Castle on King Wheels!

Possibly explains why LSL were so keen to get 6024 back to Crewe

 

Gauging on the modern railway is a precise and very complex topic. Anyone interested is recommended to register on the RSSB website and find the document
"The V/S SIC Guide to British gauging practice" which gives an 80 page overview. For more detail seek out the actual standards document, GERT8073, around 150 pages, which refers to a good many more documents.
There are several different gauges in use on the modern railway, and its worth noting that width low down, platform clearance etc, is at least as big an issue as height when it comes to steam locomotives. Every structure on the railway is recorded, and they have software which can tell them which individual structures a given vehicle can negotiate.

 

Well, the Earl has gone through Crewe without any problem.

 

Which leaves me wondering why, if the data is already available, it seems to take so long for route clearances to be approved. Do they have to manually figure out and query each separate structure on any given route? Do they not have pre-calculated limitations for each section between junctions?

 

To use a King's driving wheels on a Castle they would also need to move the holes for the crank pins, because a King's cylinders have a longer stroke. That would be difficult and I can't see it being worth the bother.

 

It can be done very rapidly... Witness Flying Scotsman's very high profile visit to the Borders Railway, which was nearly scuppered because someone had 'forgotten' to crunch the numbers. A phone call from someone 'very high up' saw it cleared in 24 hours!
There was a interesting article on this topic a few years ago in one of the mags.
Gauging today is now a lot better than it used to be due to the advent of digital scanning. All (individual) locos are now laser scanned as part of the certification process and their measurements stored & compared to known pinch points on computer. Where recent work has been done on the railway, a manual check maybe needed, but this is now a lot rarer than it was, when nearly all checks had to be done by hand. Tyseley stated a few years ago that collaboration with the railway industry has made a significant number of routes available to their Castles and indeed they have travelled far and wide in the last few years.

 

I fell about laughing at this. Have folk on here never heard of tyre turning?

It is quite possible for Castle wheels to be 6ft 6" diameter if an inch of tyre thickness has been remove through succesive tyre turning.

 

Sure? According to Cook 6'6 was below scrapping thickness for a Castle wheel, although they did turn a new set of tyres down that far for a short term experiment while developing the King design.

 

Yes - MT276 - The BR document "Examination Schedule For Preserved Steam Locos Running On BR Lines" - new tyre thickness 76mm, last turning tyre thickness 50.5mm so removal of one inch (25.4mm) of tyre thickness is permissable. That of course does not leave lots of tread wear before scraping thickness of 47.5mm is reached.

 

I think that we can see from your web-site and other sources that it is not only the modern railway where gauging is complicated - it was a complex topic in the steam age, especially on routes where clearances were altered over time.

Height problems could often be resolved by relatively easy changes to chimneys, domes and cab roofs. Width problems could be more complex, especially if the issue was width over outside cylinders. Although width problems could sometimes be higher up the body sides - eg. the LBSC had to reduce the width of guards' side look-outs that (at 9ft 2in) were OK on short 4/6-wheel carriages, but not on longer bogie carriages with greater throw-over on curves.

I think the widest locomotives in British preservation (apart from Didcot's broad gauge replicas) are the two Urie S15s on the Mid Hants, at 9ft 1in over platforms. But their large cylinders are inclined and closer together than on comparable GW engines.

 

Castle nominal wheel size is generally published as 6'8.5" (2044.7mm). I don't have any details for a Castle wheel available to me, but a standard 5'8" wheel had a 3in (76.2mm) tyre when new (GWR drawing 90394). Assuming the same for a Castle then if my sums are right the wheel diameter would be 6'2.5 (1892.3mm). So at the modern scrapping thickness diameter would be 1987.3mm or 6'6.24", which matches up to what Cook has to say about experimental 6'6in wheels running on Ludlow Castle for a limited period being below scrapping thickness at 6'6 after turning 1.25" off. But there are several assumptions there, correct me if I'm wrong.