GCR Black 5 No 45491

I believe the tube plate is a new one - but it could have been made over a year ago and been awaiting machining etc, hence the not "new" appearance....but I am only making reasonable assumptions.

 

Thanks Phil - good news either way

 

Rogers' book says the manufacturing fault was that the central portion of the stays had been machined to too small a diameter. Riddles was actually third in command at the time because Stanier was in India and S.J. Synes off sick.

 

I think I read somewhere that the previously fitted one had to be replaced because of a paperwork issue. Which has set the loco back a fair bit, presumably, as I seem to recall it had been tubed as well, before it all came to bits again.

 

...See post #24 - where it was expected to be hydraulically tested.

 

This is the new tube plate in position but not yet rivetted.


And the ashpan looking complete.

 

The tube plate has been partially fixed in place with nuts and bolts - so drilling to size and rivetting next? Also note that the various "temporary" sheds have been removed from in front of the loco shed.

 

There are a few more nuts and bolts holding the front tube plate in place and one or two small tubes have been slid into the boiler, so slow and steady progress.

 

Please might someone correct me if im wrong, but have we recently moved in to an era of fabricated tube plates, as opposed to pressed ones? This is the second such example iv seen in recent weeks.

Or have i just missed that its been going on for a while?

For clarity, a flat sheet that has been laser/waterjet cut for the tube holes, welded up to a rolled ring to form the feature for riveting to the barrell.

 

I don't know if it's universal but we still have the ability to press out a tubeplate. This is 2968's prior to fitting, taken 3 August 2017 and 6 February 2020.

 

I think fabricated tubeplates have been around for a long time - I think 6619 received one when it was first restored in the 1980s.I believe that 30825 is in the process of having a new one made at Grosmont, and I was surprised to read in"Moors Line" that it was described as Technically challenging". I was also a bit surprised to learn that it is being made by drilling the holes the old-fashioned way, rather than having them laser or water-jet cut because it was too expensive or a suitable contractor couldn't be found. Clearly a traditional pressed example would be best, but then it's a question of finding or making a correct-sized die and block.

 

Expense I can believe. If one has a decent radial drill or similar in house, outsourcing such a large part to a 3rd party will always feel more expensive. The benefit of volunteers, they are nearly impossible to compete with if you have the time to do the work.

 

I’m quite surprised that pressed tubeplates are still being made. Good to see this, though.

 

I'm sure I'm wrong in imagining that steel pressed into a former giving 90 corners is more likely to create stress cracking?? Or would a welded joint be less or more optimal?

 

Typically this is done with heat, and the steel is at the correct condition & material specification before its pressed. There are also rules on bend radii for given thicknesses. No stress cracking if done correctly.


Its horses for courses on the welded / pressed in this instance. Fabrication cost is one of the biggest drivers, and having someone design and then machine up the correct formers and then finding a suitable X hundred potentially X thousand tonne press, v having a plate laser cut and a ring rolled for the barrel then a coded welder marry the two....


I know what my first preference would be. Machining formers and pressing is intense.


FWIW I don’t really like the men with hammers and oxy torches method doing it over a small former/dolly. It looks like too much hard work to this engineer. But hey, I’m not a boilersmith...

 

IIRC, that's what they did for the Duplex in America.

Dunno if this will work, but it seems to be men with hammers
https://prrt1steamlocomotivetrust.org/boiler-gallery/

 

That’s the way most firebox and tubeplate flangings are done these days. I think only the South Devon have a suitable press for doing the job - a 700 ton vicing press. Israel Newton did have a smaller one but I don’t know it’s current position