Boilers & Accidents

I hadn't read that report before, it's absolutely fascinating, and not a little salutary. Very interesting how, given a disconnect between the blowing off point and the pressure reading, only one driver appears to have considered that the safety valve was at fault - everyone else considered it must be a fault with the pressure gauge.

Also interesting all the comments about injectors not working when the loco was at or near blowing off point, which seemed to have been so common on that class as to be more or less an accepted feature rather than a fault.

Tom

 

There are alarming similarities between this and the traction engine boiler explosion in Ohio which killed five people including the owner/driver in 2001. Again there was a crownsheet failure due to low water but, in this case, exacerbated by corrosion which had reduced the plate thickness from .375" t0 just .087" in places. Additionally there were 'dubious' welds around some of the crown stays and the (inoperative) fusible plug. The pressure gauge was reading 25-30 psi 'low' but, most seriously, the safety valve could not lift at all. IIRC post accident testing of the valve was abandoned at 600 psi when it still hadn't opened.
Both accident reports highlight poor maintenance and knowledge/training. Thankfully, since then, there has been an 'across the board' tightening up of the regulations but we underestimate the ability of fools at our peril!
Ray.

 

Was this the Case traction engine? I have a magazine somewhere with the article on this explosion... IIRC the engine was thrown 25ft. up in the air with the force of the explosion, and the smokebox door was blown clean off and killed the owner and others stood a distance away from the engine.
It was stated in the article that traction engine owners were not, at the time, bound by Law to have boilers tested... It was down to their own judgement as to the boiler / firebox's condition. I sincerely hope that the Law has been changed since that event.

Richard.

 

The problem is that in the U.S. there is Federal law, State law and county law. The rules on boiler inspections vary from state to state and in some counties regulation is next to non-existent. IIRC in the case of railway locos, if they cross state lines higher levels of FRA inspection apply. Even in the U.K. one could legally steam an uninspected, uninsured boiler provided it is totally on your own land to which the public are not admitted - but you'd be an idiot to do so!
Cheers,
Ray.

 

The fact that injectors failed to work on these engines with 200 psi boilers suggests that they may have been designed for lower pressures. My weight diagram book gives a working pressure of 175 psi for the G2s. I wonder if some locos had higher pressure boilers fitted but the injectors were not changed. Injectors have a limited pressure range over which they will work. It is not unknown for injectors working towards the top end of their range to give troubles on some days. They are affected by water temperature, atmospheric pressure and fouling of the cones restricting the water flow (my experience is with miniature injectors but the physics is the same).

 

I think it was stated in the report that locos of that type were the only ones on the LNWR with 200psi boilers, all other locos being pressed to 175psi or lower. So clearly it is conceivable that the LNWR standard injectors didn't work well at the higher pressure, being optimised for a lower range.

Even so, I still think it is noteworthy that the railway appears not to have considered whether designing a higher-pressure boiler may not also have required changes to ancillaries, particularly important ones like the injectors! After all, the new boilers didn't appear overnight, so there must have been time to consider the issue. From the driver comments in the report, it appears that it was a well known problem, and at least some of the drivers deliberately aimed to run at a lower pressure so as to ensure that the injectors worked reliably. Which is entirely understandable behaviour, but rather negates the advantage of fitting the higher pressure boilers in the first place.

(As an unrelated aside: accident reports are often goldmines for finding out about working conditions and details entirely or largely unrelated to the main issue at hand. Most knowledge about how the LBSCR Terriers were fired in the nineteenth century comes from comments made during an investigation about a death caused by a non-working water feed pump!)

Tom

 

could be wrong , but I think that was Abermule

 

It was Ditton, but the barrel hadn't broken away. It had been driven into the firebox by the force of the collision, but the two were later lifted as a unit.

 

that looks conclusive lol. .... but in red for danger , there is a pic of the 2-4-0 with a broken back if that is of interest

 

In my copy of Red for Danger (1998 reprint - the earlier copy fell to pieces through re-reading...) shows the 2-4-0 at Ditton Junction. Give or take the existence of boiler cladding present in the photo in Rolt's book and absent in @LMS2968's photo, I'd say they are the same boiler; in particular both show that the axis of the barrel and the firebox are no longer co-linear. (The photo here is the same as in Rolt's book: http://www.railwaysarchive.co.uk/eventsummary.php?eventID=81)

The accident report (linked from the link above) says "The barrel of the boiler was partially separated from the firebox casing, all the rivets being sheared off from the top as far down as the centre of the boiler on both sides". Rolt describes that as "shearing clean away" which isn't quite true (they remained connected), but clearly such an event would - directly attributable to the impact - have led to a very rapid venting of steam and most of the water from the holes in the boiler thus created.

Tom

 

yep - dug out my copy (1982)

Colonel Yorke said "there is no record of any previous accident in which the engine has broken its back, as in this case "

 

List of damage to engine and tender as itemised in the BoT report:


Damage to Engine and Tender.

Engine 1529, "Cook", 6 ft. 6 in. coupled passenger.-

Frames badly damaged and knocked out of square, left frame bent round at front end :
cylinders broken and pushed back two feet:
pistons damaged ;
slide bars broken ;
motion and plate broken ;
reversing shaft and gear bent and brackets broken, screw wheel broken ;
connecting rods bent badly ;
coupling rods right-hand bent :
valve spindles broken ;
brake gear bent and broken, steam brake cylinder broken ;
wheels, leading, axle bent, one inch out of gauge, driving, axle bent, half inch out of gauge, one spoke broken in right-hand wheel, trailing, axle bent, three-quarters inch out of gauge ;
vacuum pump damaged and pipes bent and broken;
boiler, steel tubeplate bent back, copper tubeplate bent back, and broken through the second row of tube holes from bottom;
boiler barrel broken from fire-box casing, all rivets sheared off the top and as low down as the center of boiler on both sides ;
fire-box front and back casing plate knocked in (back casing plate has hole in right-hand side by coming in contact with cant iron footplate) ;
smoke box and lagging plates for boiler badly damaged ;
steam pipe in smoke-box badly damaged ; blast pipe broken ;
regulator box and valve broken but valve shut ;
regulator handle bent (this was not in position on boiler, but came with other material in waggon) ;
safety valve, lever bent, but otherwise in good .condition ;
whistle stand broken off boiler, but was attached to cab, also pressure gauge, steam
and air boxes and some small pipes attached to cab ;
cast iron footplate broken at front and back ends and casings on top of footplates broken ;
cab damaged ;
splashers damaged ;
panels broken.


Tender No. 1707, 1,800-gallon, attached to engine No. 1529, "Cook"-

l pair of wheels. bent axle and one spoke broken: 1 pair of wheels. bent axle :
tender; frame beyond repair ;
6 axle boxes broken:
6 hornplates and blocks beyond repair;
brake work beyond repair;
draw bars and connections with the exception of spring plate and box beyond repair;
tank and mountings beyond repair ; 1 dip pipe complete, beyond repair.

I hate to take issue with the good Lieutenant-Colonel, but the boiler - firebox structure retained sufficient mechanical integrity to survive being lifted that way.

 

I read that - there was very little that was undamaged.

Which raises the thought - what subsequently happened to the loco? Was it written off, or rebuilt? Clearly, "repairing" that little lot would be tantamount to new construction, but then you get into the vagaries of what was done on the capital and what on the revenue account ...

Tom

 

that'll be repairable then ! nowhere near as bad as 6242

 

It didn't survive, and is not on Yeadon's list for 1912.

6242's damage was severe, but how severe? The RH front main frame was bent back and sheered off ahead of the outside cylinder, but the LH one seems to have only a couple of minor bends in it and probably straightenable. A new RH half frame would work. The RH cylinder was smashed and the inner also badly damaged and would need replacement. The RH motion seems to have perished, except perhaps for the coupling rods. Running gear? I don't know. The loco ran derailed for about a hundred yards but the wheels, etc. were not involved in the collision itself. The boiler of course was repaired and back in use before 6242's return to traffic. The rest was platework, although it was LOT of platework! But I'd suggest it was a matter of whether or not the mainframes were knocked out of true. The trailing frames were reused (Allan C Baker, and ex-Crewe apprentice confirms this) so probably not. Looked at in that light, 6242 was 'do-able', but it must have taken a lot of pondering, even so.

 

i've read the very interesting stuff you posted a while back 6424/6202/71000. most enlightening . I've always had a deeper interest than most re the harrow accident because I spent many hours on the platforms when I lived at Wealdstone.

windward islands did most of the damage to 6242 , and most people will have seen what happened to the Jub.
Crewe was highly skilled at metal bashing and welding . I suspect they took most of the frame to pieces and rebuilt it on a jig . we will probably never know why 6202 got the chop , but we would have never had the pleasure of seeing 71000 in preservation if she had also been rebuilt . it would have been interesting to see what numbers were stamped on 6242 motion when she returned to traffic.

I have long held a theory as to the cause of the crash . ............there was a set of LNWR signals on the south side of the road bridge .70+ ft. high . the accident report mentions low lying fog on the day . those signals could be seen by trains approaching from the north .ABOVE the road bridge , and they were "off" for the local standing on the up fast line . could it be the crew of 6242 saw the board was off , looking OVER the fog , and thought they had the road ?

 

It'll polish out ...

Tom

 

From photographs 46202 looks less damaged than 46242, yet it was scrapped.