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Longest Tank Engine Runs

Discussion in 'Steam Traction' started by johnofwessex, Jan 14, 2019.

  1. Monkey Magic

    Monkey Magic Well-Known Member

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    This prompts another question for me. How often are tanks blanked off/dummy tanks? I recall the first time I had to fill up a tank loco with large tanks and was then surprised to see that the water only went in half the tank. I wondered at the time if it was a stability issue with the loco but assumed it was just this loco. Is a Prairie, Pannier or BR std tank blanked off at all? (Off the top of my head of tank locos with big tanks)
     
  2. bluetrain

    bluetrain New Member

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    Thanks for that. I believe that some large tank types on the LMS also had stability problems, but that soon ceased to be an issue as they got replaced by LMS standard 2-6-4 tanks.

    Billinton of the LBSC probably produced the most successful type of Baltic tank in the British Isles - certainly the best looking!

    I note that the LSWR had been one of the railways criticized by the Railway Inspectorate for using tank engines on fast trains and wonder if this had an impact on subsequent LSWR locomotive policy. Although the LSWR had some of London's heaviest commuter traffic, it built no passenger tanks larger than the M7, first introduced way back in 1897. Maybe that was just as well. LSWR loco-men might turn in their graves at the thought of a Drummond 4-cylinder 4-6-4 tank.
     
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  3. johnofwessex

    johnofwessex Part of the furniture

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    What loco was that you were filling up?
     
  4. Jimc

    Jimc Well-Known Member

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    There were some experiments with weight distribution on the GWR large prairies, which saw tank capacity temporarily limited in the late 20s, but it was increased again. It would surprise me if many classes were running with half empty tanks, since smaller tanks would weigh less, cost less and give better visibility.
     
  5. Jamessquared

    Jamessquared Nat Pres stalwart

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    The LSWR had an accident - again, fortunately without serious consequence - in which an M7 left the road near Tavistock in 1898. At the time, the loco was almost new and the carriages had all recently been shopped. The p/way had been laid as recently as 1890, but using second hand materials and it seems the combination of heavy axle load and the speed was too great for the relatively light rails used, causing the p/way to spread under the locomotive. So again, it looks like it was the combination of loco and p/way rather than uniquely problem with the loco, but in any case, the LSWR withdrew the locos from west of Exeter and used them predominantly on suburban services round London, where the p/way was better and speeds were lower.

    The accident report is here: https://www.railwaysarchive.co.uk/documents/BoT_Tavistock1898.pdf The Inspecting Officer makes reference within to the earlier accident on the GWR at Doublebois, which also involved an 0-4-4T.

    Tom
     
  6. Jamessquared

    Jamessquared Nat Pres stalwart

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    Just thinking a bit more about this: the obvious cause was electrification. An M7 was sufficient for the train weights of suburban traffic on offer ca. 1900, and by time the weights went up (post World War I) and other companies built bigger tank locos to handle the traffic, the LSWR was already well on the way to electrifying all its suburban services.

    Tom
     
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  7. Steve

    Steve Part of the furniture Friend

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    A higher centre of gravity should have a lesser effect on the potential for spreading of the track as the resultant force is nearer vertical. The higher centre of gravity will lead to a greater tendency to roll, though, and consequent overturning.
    Personally, the smoothest riding locos I have ever ridden are the BR 2-6-4T's, even on relatively rough track.
     
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  8. bluetrain

    bluetrain New Member

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    Many thanks for your thoughts here and for the link in your earlier post to the Tavistock accident report. The LSWR board and management may or may not have felt that the Railway Inspector's criticism of M7 use on fast trains was justified, but clearly they felt the need to take the locos away from fast work in areas with possibly inferior track, and might have been put off any idea of a larger passenger tank. Batches of M7s continued to be built until 1911, so these engines must have been felt adequate for LSWR suburban passenger duties up to that time.

    I believe that the first LSWR electric trains (apart from Waterloo & City) started running in 1915/16, but planning must have started a few years before. So as you suggest in your post, that was probably just at the right time to remove the need to introduce a larger passenger tank.
     
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  9. Cartman

    Cartman Member

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    Maybe the LYR thought along the same lines as they built large numbers of the excellent 2-4-2 tanks which handled their suburban traffic. They did a small batch of inside cylinder 2-6-2 tanks in an attempt to enlarge them but they were a bit rubbish. Also, they were early pioneers of electrification with the Liverpool to Southport and Manchester to Bury lines.

    Also one of the 2-4-2 tanks was involved in a derailment at Charlestown curve near Hebden Bridge, the circumstances were similar to the Tavistock accident with the M7, as in Tom's post
     
    Last edited: May 15, 2019
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  10. andrewshimmin

    andrewshimmin Well-Known Member

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    The L&Y didn't have a bigger tank, but Hughes did introduce his 4-6-4Ts based on his L&Y 4-6-0 early in his LMS tenure.
    The Lanky Radials, in their final superheated form, were more powerful than you might think, and adequate for all L&Y suburban needs, even with the fearsome gradients involved.
    But as you say, there was one very tragic accident, and they were officially withdrawn from express work, although in practice I believe they drifted back into front line service.
     
  11. Jamessquared

    Jamessquared Nat Pres stalwart

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    It was an odd accident. The Inspecting Officer talked about instability of the locos at speed; my assumption is that he is talking about a combination of a fore-and-aft movement possibly imparted by water surging in the tanks and an insufficiently tight coupling to the train; combined with a side-to-side rocking of a two cylinder loco. Eventually that proved too much for the track given the high axle load on the leading axle and the (possibly) high speed: he conjectured that the speed was rather higher than that estimated by the loco crew.

    Reading between the lines, I cannot help wondering whether the District P/Way Inspector knew the line probably wasn't up to the standard necessary but colluded with the ganger to try to divert attention. The track in question consisted of 30 foot lengths of 82lb/yd rail, which had been taken second hand from the Salisbury - Templecombe section of the mainline and used as new to build the Lydtor - Plymouth section. As such it would probably already have been nearly 30 years old when laid (the Salisbury - Templecombe line was laid in about 1859; and the line at Tavistock was laid in 1888). The District P/Way inspector asserts that in his view the derailment was caused by an old contractor's fishplate left behind after construction, which was laid -- by person or persons unknown -- on the left hand (outside) rail, causing the loco to derail. The Inspecting Officer dismisses that theory in fairly gentle terms and suggests instead that the gauge spread beneath the loco. I can't help wondering whether the company p/way men had a hunch the track was insufficient, and concocted the fishplate theory to try to throw the inspecting officer off the scent.

    Tom
     
  12. Jimc

    Jimc Well-Known Member

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    The Doublebois accident involved the 3521 class, the one that Holcroft described the ride as being "like a rat shaken by a terrier". Notorious for their impact on the track they were definitely not one of Dean's finer moments! They had a short coupled wheelbase. They were eventually rescued by being converted to 4-4-0s in a rebuild which way exceeded anything Jarvis managed in which the outside frames were reversed and shortened, and the inside frames lengthened at the front and shortened at the back, with a piece added on both sets between the drivers to lengthen the wheelbase!
    Its interesting in the Doublebois report that the loco crews don't say anything adverse about such notorious rough riders, but the track workers had plenty to say! We should remember that even in these investigations the railway company witnesses would always be conscious of the boss metaphorically looking over their shoulder...
     
    Last edited: May 16, 2019
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  13. Cartman

    Cartman Member

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    Weren't the 3521 tank locos converted into 4-4-0 tender engines after this accident?
     
  14. Jamessquared

    Jamessquared Nat Pres stalwart

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    I think from @Jimc ’s description above about the frames being reversed, the answer is yes!

    I do wonder slightly though about what the workshop reality (rather than description) of those changes was. You reverse the frames, cut some bits off one end; add some bits at the other end; cut them in two to insert an extra length between the driving wheels; and all that on four separate frame plates. Then the cylinders change end, so that means new drilling to accommodate; reposition frame stretchers, reposition motion bracket; probably a host of other minor changes. Surely in that instance simply cutting new frames would have been less labour as a practical reality, even if conceptually the process was as Jim described?

    Tom
     
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  15. Jimc

    Jimc Well-Known Member

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    Oh gosh yes, I forgot to mention the 4-4-0 bit. I should have! I''ve added it now.
    I did think that the cylinders would be undisturbed, but the drive must have changed from the trailing pair to the leading pair, so that can't be right either. I don't have any drawings of the 3521s in their hapless original form. I should try and find something!
     
  16. Cartman

    Cartman Member

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    I've only found a photo of a model of one in its form as an 0-4-4 tank. The rear bogie has outside frames and a very short wheelbase. I get the impression that Dean's designs were a bit like Drummonds, either very good or very bad.
     
  17. RLinkinS

    RLinkinS Member

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    I am sure that the design of the pony truck and the trailing bogie will have an effect on the riding of the loco. The Southern moguls and River class had pony trucks with inclined slides to control the slide movement. The moguls did not ride particularly well at speed and I put that down to the pony truck design; this will also have affected the Rivers. Whthe engines hunted at speed this would cause water in the side tanks to slosh around and would initiate rolling. There are thus several factors will affect the riding of a loco which will all interact. I expect that the BR class 4 tanks had spring side control for the pony truck (and bogie?) with a significant pre load on the side control springs. This was a lesson learned in the 1930s, after the Southern locos were designed.
    The whole Southern mogul family had a repution for not riding smoothly. The pony trucks had Cartazzi slides to control the side movement and I expect this was part of the problem. Spring controlled pony trucks with appropriate intial spring loads give much better riding. I believe BR locos are fitted with spring side control.
     
  18. 8126

    8126 Member

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    O.S. Nock wrote quite favourably about the ability of the M7s to run fast and smoothly on outer suburban trains to Alton and the like, where you might expect a reasonable turn of speed, but apart from the old junction at Runfold the Alton line is pretty straight and well aligned. I think engines with no leading carrying axle are always going to be a little sensitive to track irregularities at speed; I'm sure I remember reading that the Gladstones had a reputation for hitting crossings with a bit of a thump as well, but then they were always intended to be main line engines.
     

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