Last set of BR or older era boiler tubes?

I would have thought th North Eastern duo Class M 4-4-0 1621 withdrawn 1945-6 and Class 2-2-4 [LNER X1?] 66 Aeroilite withdrawn pre-war in the thirties. Neither of which has steamed since, so shold still have LNER tubes......

 

Lea Wood pumphouse (which fills the Cromford canal from the river Dewent near the bottom end of Cromford and High Peak Railway) has what essentially amounts to two 4f boilers that were installed by the Midland Railway to run the beam engine in the early 1900s. These boilers are both still serviceable(it's run on bank holiday weekends), and both are still tubed with brass or copper tubes that are certainly pre1960, and possibly pre1940 (I'm unclear when the pump fell out of regular use, although it was "found" in near working order by preservationists in the 1970s)

 

Are they not subject to some sort of internal examination only possible if the tubes are removed?

 

They are not locomotives. The requirement for this is one imposed by the ORR in their guidance on locomotive boilers, which was largely based on BR practice. The Pressure Systems regulations don't specifically require it and if your written scheme doesn't, it is not necessary. I bet there are many industrial boilers with tubes 30 or more years old, especially if they are gas fired. When I first got involved with industrial loco boilers back in the 60's the boiler inspector wasn't interested in the tubes, other than perhaps noting they were thin. No requirement for an internal exam, other than through openings. The requirement was for a hydraulic at 6 years and all lagging removed at 10 years, plus a hydraulic.

 

Indeed though I'm reminded of multiple fatalities following an incident with a traction engine boiler in America several years ago where the regulations were fond wanting as was the condition of the boiler.

 

Indeed there was an explosion, due to the poor condition of the boiler. Necked crown stays, safety valve not working and pressure gauge reading low were just three contributing causes. However, unlike in the UK, there was no requirement in Ohio to have the boiler examined.
Boiler explosions do happen, unfortunately, the latest that I know of being in India in November. There is an interesting list of explosions on Wiki although it is far from complete. Most, but not all, recent boiler explosions seem to be in the US. The report on the Gettysburg explosion is a very interesting read and shows how ignorance and lack of training and maintenance can all contribute to disaster. (see http://www.athra.asn.au/library/Loco_1278_Boiler_Explosion.pdf) AFAIK the last locomotive boiler explosion was in 2000 when a Baldwin 2-8-0 exploded in Cuba (although not on the Wiki list.) In this case it was a comparatively rare failure of the boiler barrel due to corrosion. Most boiler explosions involve collapse of the firebox due to overheating or broken stays. 62005 came close to it a couple of years ago but we have been lucky in the UK. So far.

 

....along with sitting at an angle with the front of the firebox uncovered whilst the rear (and 'plug) probably would have been covered. The thickness of the 'box in this uncovered area having corroded down to about 2mm wouldn't have helped either. Altogether not a great example of boiler condition.

 

Not quite .... IIRC from reading the official report the engine was moving and, when ordered to stop by a police officer, the water (what little there was) sloshed forward momentarily and 'flashed' to steam when the wave contacted the, now overheated firebox crown, on its return. The safety valve was an untested replacement which failed to open (later tested to 600psi without opening) and the fusible plug had been 'plugged' with a bolt rendering it inoperative. This was yet another case where poor maintenance, combined with incompetence and lack of regulation lead to a disaster. In the U.S. there are county, state and federal boiler regulations which vary from non-existent to very stringent but generally they have been tightened up in recent years.
Ray.

 

Here is a university engineering analysis of the failure of the heavy Case traction engine boiler failure:
https://www.google.se/url?sa=t&rct=...656/download&usg=AOvVaw0QDu2NoCbBuHFB9Xk7t7IU

Sorry for the long address, don't know how to link to the document directly.

As indicated, a severe combination of lack of maintenance and operating skills as well as lack of control rules and structures.

 

I believe this link is to a quote of the official report: http://www.dli.mn.gov/ccld/BoilerIncidentsHobby.asp

This states the safety valve was subsequently tested and found not to lift with pressures up to 200psi, which is still somewhat higher than the 125psi it should have been set to, but not as high as the 600psi you've quoted.

The report states that there was evidence the fusible plug had not been removed for quite some time, but does not appear to state it was plugged with a bolt. It was removed after the incident and sent for metallurgical examination. This concluded that it did show slight signs of overheating, but that it did not melt and blow out. There's no suggestion of it being plugged and incapable of blowing out.

The report suggests the firebox had already 'quilted' some time earlier due to the excessive wastage of the plates, allowing scale to build up in the depressions which worsened localised overheating. The conclusion was that the non-operating safety valve wasn't a factor as the pressure in the boiler is likely to have failed at around 90psi. This is somewhat different to your suggestion there was a sudden flashing of high pressure steam.

This report on the incident, which quotes official sources, https://www.farmcollector.com/steam-traction/final-report-tragedy-medina-county-fairgrounds

...comments on the engine being in a "static, or near static condition". Also that, "The report says that a combination of corrosion and erosion due to age, and excessive heat on the right front of the crown sheet (which the report says was exposed and had no water covering it, a condition caused by the tractor being positioned on a mild grade that placed its left rear down low) caused the crown sheet to fail. The report cites discoloration of the steel in the front part of the crown sheet as indicative of abnormally high heat. The fusible plug was located at the rear of the crown sheet, and investigators theorize it was covered with water while the forward part of the crown sheet was not, hence explaining the fusible plug's failure to melt out."

Andrew Semple's account of the incident (Then NTET chairman, and at the time on holiday in the general area - he travelled over a few weeks later, identified who he was to the authorities and was shown preliminary investigations and reports). Can be seen in the following link: http://www.nlsme.co.uk/articles/boiler_explosion.pdf

This records that police officers saw the engine driving down the road shortly before the incident with no apparent problems. The engine then stopped on arrival at the display area. It was only after the engine had stopped that the police officers started to approach to discuss the damage that had been caused to the newly resurfaced road. There's no suggestion that the police officers ordered the vehicle to stop, and once again it states that the engine was stationary at the point of failure, so not in a position for water to surge forwards. This account also records that the plug was correctly filled with tin (as required in USA) and had not melted - so no suggestion of it being plugged with a bolt there either.

Andrew does refer to rumours about it being low on water when it stopped, leading to a surge when it moved again, but he didn't feel this was really credible: "There is a theory being widely discussed that the engine was low on water when it stopped moving at the showground. This may have allowed part of the tube plate to become excessively hot such that when the engine next moved water surged and covered the heated area, which suddenly created a large volume of steam thus precipitating the collapse of the crown. However this overheated area would be adjacent to the fusible plug and since the tin filling has a relatively low melt point it is difficult to imagine how this could occur without the filler melting. I understand that the showground area where the explosion occurred is relatively flat.". Again no suggestion the fusible plug was in any way rendered incapable of operating. Obviously Andrew isn't/wasn't an official investigator, but the other references to official reports don't seem to support this theory either.

Across the different accounts there are minor differences: Was the safety valve tested up to 200psi, or 250psi without it lifting? Should it have been set at 125psi, or 160psi? But the general points do agree with each other, and with the greatest of respect, don't seem to confirm the details you've stated.

 

In the DLI report, John D Peyton estimates that the 90psi explosion released 28,000,000,lbs of force, I'm having trouble in reasoning this out, can somebody provide a formula for arriving at this figure, or do we just have to take it as read?

 

You're not the only one, especially as it refers to 'energy released' in terms of 'pounds of force'. Perhaps definitions are different in the U S of A.

 

Looks to me as though it's phrased as "28,000,000' lbs" which would be foot-lbs, a unit of energy (38,000,000J). Energy would make more sense!

 

That would make more sense per se, but doesn't arrive at a formula to calculate how 90psi can blast something weighing in the region of 10 tons 10 to 12 feet in the air.

 

Well, it is going to be rather complicated but, in simple terms, the energy required to lift any given mass to a specific height is governed by the simple formula E = mgh, which works out at 2.637 x 10*6 ft lbf or 33,763 Btu, if my calculator has guessed correctly. If you really want to you can calculate the maximum velocity achieved by using v*2 = u*2 +2fs and from that calculate the average force required to accelerate the mass up to that velocity using P = mf and, knowing the cross-sectional area of the object, you can calculate the average psi required. Personally, I wouldn't bother, though.

 

Thanks for the formulae,etc. As you said in the last sentence, you wouldn't bother, and I don't suppose any-one else has, which brings us back to taking things as read.


Having been involved with a few 'uncontrolled releases' over the years I'm afraid that I find 90psi causing the amount of damage recorded here as beyond the realms of possibility.

 

Looking at the photo posted by Steve of 80150 on the MHR restoration and overhaul thread. The photo shows the boiler tubes still in situ.

https://www.flickr.com/photos/arleimages/39116695720/

 

North Stafford No.2 still has a set of brass tubes in, albeit fitted at Walkden works by the NCB in 1960

 

There has been a lot of speculation about what exactly happened that day but I have seen the dash cam footage from the patrol car of the tractor entering the fairgrounds and you can seem them trying to put water in the boiler- steam was coming out the injector overflow. On penberthy type injectors you can generally tell it's not picking up water if it steam is running out the overflow (and it didn't look like water was coming out so it wasn't the check valve malfunctioning). Additionally I have heard on good authority from someone who talked to one of the people that were close enough to the engine to get hospitalized that she heard one of the men on the operators platform yell an explicative just before the firebox went so they knew something was wrong. I would say either they started running water again onto a now empty crown sheet or as they were backing into the spot the low water sloshed backwards, then forwards off the crownsheet as the tractor stopped, before returning and flashing on a red hot bare crownsheet. We will never know 100% because everybody on the tractor died but it is likely it was one of those two things. The boiler should've never been fired in the state it was in (read the report it was atrocious) with a malfunctioning safety valve and pressure gauge to boot but you could have the best safety valve around and it wouldn't keep up with flashing steam. I would feel safer with a set of pre-grouping tubes that passed a hydro test with a crew that's competent and watches their water than a set of brand new tubes with an incompetent crew any day. There have been rumors (which I can't substantiate because I was but a wee tyke when Medina happened) that the crew had a history of running their water low at shows with the attitude "it's my engine, I can do what I please" and that they were told not come back to several different threshing shows. Whether or not that's true or a load of bologna it's up to you to decide. Really it was probably operator error more than lack of maintenance (again that boiler should have NEVER been fired). Ohio revised its boiler laws significantly as a result but no matter what country you go to you will have guys that think they are more clever than the engines.

 

Post deleted.

Richard.