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Tornado's boiler to return to Germany
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Teaboy1
Member
Mmmm........hollow stays.........steel firebox.......fabricated foundation ring........not really LNER stuff was it??
The A1 foundation never claimed that they were building a historical replica but a modernised design of the A1. A design based on the A1 but taking advantage of modern developments. At least that's how I've understood the design to be.
DarloRich
Veteran Member
That is correct Ainsworth - a shame North Roads finest will be out of action for longer than anticipated.
Update - seems to have been pulled out of the NRM workshop. Was in the little yard last night and is now sat outwith the NRM. Bolier still attached to body but without cladding and cab structure.
Update - seems to have been pulled out of the NRM workshop. Was in the little yard last night and is now sat outwith the NRM. Bolier still attached to body but without cladding and cab structure.
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Teaboy1
Member
Modern developments are fine but it must be remembered that some 80 years went into finding tried and trusted methods by the old groups, if it 'aint broke....don't fix it !!
Not sure how these new stays are constructed because no one has really stuck a drawing up to see. Anyway to basics, lets assume firebox is some 100 ft sq (10 ft x 10ft) and boiler press = 180 psi......so thats 100 x 144 x 180 = 2 592 000 lb trying to compress just the firebox.....assume 259.2 stays just around fire box and thats 10 000lb by my guess per stay.
Now old method with copper firebox meant that the outer shell of steel boiler plate supported a "soft" copper fire box and being soft it would deflect while the steel wont. Therefore any stays that were a wee bit shorter than its counterparts would take the load initially and the surrounding copper gives a wee bit until all load is distributed evenly to all stays and all stays are eventually roughly loaded the same due to the give in the copper. Im talking only a few thou here chaps, its very difficult to load all stays up evenly even using Crewe/Swindon/Doncaster practices with external nuts top & bottom and just stays run through inner/outer without any mis-alignment during running-in. Anyway if we now have a steel firebox & shell, all welded and totally rigid, there is no "give" in 'owt.....those colossal forces are still present and we have hollow stays (Monel I assume)....we have vibration...we have expansion & contraction.....but no give in anything. Therefore our "short" stays takes a huge force until it stretches a wee bit and allows its counterparts to receive some load until it too stretches and puts a bit of load back onto previous stay....but its probably gone past its yield point and the damage is done.
Cut&paste aka Wiki;
Compared to steel, Monel is very difficult to machine as it work-hardens very quickly. It needs to be turned and worked at slow speeds and low feed rates. It is resistant to corrosion and acids, and some alloys can withstand a fire in pure oxygen. It is commonly used in applications with highly corrosive conditions. Small additions of aluminium and titanium form an alloy (K-500) with the same corrosion resistance but with much greater strength due to gamma prime formation on aging. Monel is typically much more expensive than stainless steel.
Monel alloy 400 has a specific gravity of 8.83, an electrical conductivity of approximately 3.4% IACS, and (in the annealed state) a hardness of 65 Rockwell B.[3]
Hollow stays I would assume are beefed-up a wee bit due to loss of CSA from drilling but Im clueless as to how much and what thread form they use. Old 'uns typically BSW while DB must doubtless use metric (see different angle of thread & raduised root )...anyway Im rambling now...!!!
Point is gents, those boilers are not just bits a steel & stuff, some 80 + years development went into them. Sure we have steel fireboxes in all US locos, Bullied locos and almost all Beyer Garratts and they worked...sort of. But dont abandon old tried & tested methods.....the Kings new clothes....etc etc.
If Im talking bull, please correct my ignorance....
Not sure how these new stays are constructed because no one has really stuck a drawing up to see. Anyway to basics, lets assume firebox is some 100 ft sq (10 ft x 10ft) and boiler press = 180 psi......so thats 100 x 144 x 180 = 2 592 000 lb trying to compress just the firebox.....assume 259.2 stays just around fire box and thats 10 000lb by my guess per stay.
Now old method with copper firebox meant that the outer shell of steel boiler plate supported a "soft" copper fire box and being soft it would deflect while the steel wont. Therefore any stays that were a wee bit shorter than its counterparts would take the load initially and the surrounding copper gives a wee bit until all load is distributed evenly to all stays and all stays are eventually roughly loaded the same due to the give in the copper. Im talking only a few thou here chaps, its very difficult to load all stays up evenly even using Crewe/Swindon/Doncaster practices with external nuts top & bottom and just stays run through inner/outer without any mis-alignment during running-in. Anyway if we now have a steel firebox & shell, all welded and totally rigid, there is no "give" in 'owt.....those colossal forces are still present and we have hollow stays (Monel I assume)....we have vibration...we have expansion & contraction.....but no give in anything. Therefore our "short" stays takes a huge force until it stretches a wee bit and allows its counterparts to receive some load until it too stretches and puts a bit of load back onto previous stay....but its probably gone past its yield point and the damage is done.
Cut&paste aka Wiki;
Compared to steel, Monel is very difficult to machine as it work-hardens very quickly. It needs to be turned and worked at slow speeds and low feed rates. It is resistant to corrosion and acids, and some alloys can withstand a fire in pure oxygen. It is commonly used in applications with highly corrosive conditions. Small additions of aluminium and titanium form an alloy (K-500) with the same corrosion resistance but with much greater strength due to gamma prime formation on aging. Monel is typically much more expensive than stainless steel.
Monel alloy 400 has a specific gravity of 8.83, an electrical conductivity of approximately 3.4% IACS, and (in the annealed state) a hardness of 65 Rockwell B.[3]
Hollow stays I would assume are beefed-up a wee bit due to loss of CSA from drilling but Im clueless as to how much and what thread form they use. Old 'uns typically BSW while DB must doubtless use metric (see different angle of thread & raduised root )...anyway Im rambling now...!!!
Point is gents, those boilers are not just bits a steel & stuff, some 80 + years development went into them. Sure we have steel fireboxes in all US locos, Bullied locos and almost all Beyer Garratts and they worked...sort of. But dont abandon old tried & tested methods.....the Kings new clothes....etc etc.
If Im talking bull, please correct my ignorance....
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60163
Member
Damn, I wanted to see it on the SVR in April 
The A1 group were building a new boiler, so it has to comply with today's standards. They simply could not just build a 1940's boiler.
I presume 60163 has flexible stays fitted in key areas. That would be standard practice in a steel welded firebox. Hollow stays are also widespread on welded boilers - the hollow centre acts as a "tell tale" in the event of a fracture.
This loco is effectively a prototype - things are going to go wrong. However, i would suggest that is a lesson to those who think that new build replicas are a panacea for the preservation movement. The boiler was lifted late last week, and placed on its low loader. The very best to the group for getting it sorted.
Teaboy1
Member
If I may draw ones attention to the following passage;
Nigel Gresley Locomotive Engineer by FAS Brown. Pub Ian Allen c.1961 p185.
"The second V4 engine No 3402 (later 61701) was completed in March 1941. It was not named, but drivers naturally dubbed it Bantam Hen. No. 3402 was equipped with a Nicholson thermic-syphon and an all-steel welded firebox. Of these Spencer commented 'Gresley intended to obtain a definite comparison between the steel firebox of 3402 and the copper firebox of 3401 but wartime conditions brought the experiment to a close in 1945. The welded firebox and the thermic-syphon gave very satisfactory service but trouble was experienced with broken side stays and this led to the decision to fit a copper firebox similar to that of 3401."
I hope this illustrated the wisdom of the Gresley years and the 80 years experience of Doncaster / Crewe / Swindon ..........Darlington....!!
.....
--- old post above --- --- new post below ---
I dont agree that the "loco was effectively a prototype..." Arthur did all that work 60 odd years ago and Nigel did his bit 30 years before that. Not heard of flexible stays though....do tell, I always keen to learn.....never-say-never in my book!
Anyway good luck, make sure DB tension those stays evenly!
Nigel Gresley Locomotive Engineer by FAS Brown. Pub Ian Allen c.1961 p185.
"The second V4 engine No 3402 (later 61701) was completed in March 1941. It was not named, but drivers naturally dubbed it Bantam Hen. No. 3402 was equipped with a Nicholson thermic-syphon and an all-steel welded firebox. Of these Spencer commented 'Gresley intended to obtain a definite comparison between the steel firebox of 3402 and the copper firebox of 3401 but wartime conditions brought the experiment to a close in 1945. The welded firebox and the thermic-syphon gave very satisfactory service but trouble was experienced with broken side stays and this led to the decision to fit a copper firebox similar to that of 3401."
I hope this illustrated the wisdom of the Gresley years and the 80 years experience of Doncaster / Crewe / Swindon ..........Darlington....!!
.....
--- old post above --- --- new post below ---
I dont agree that the "loco was effectively a prototype..." Arthur did all that work 60 odd years ago and Nigel did his bit 30 years before that. Not heard of flexible stays though....do tell, I always keen to learn.....never-say-never in my book!
Anyway good luck, make sure DB tension those stays evenly!
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