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Loco to Tender Couplings

Discussion in 'Steam Traction' started by johnofwessex, Jan 26, 2022.

  1. johnofwessex

    johnofwessex Resident of Nat Pres

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    How are loco's coupled to their tenders and how interchangeable are tenders?

    The Bluebell Thred refers to the 'C Dog' not a profanity but for a period the Dukedog ran with the tender from the C Class.

    Also during the 1948 exchanges a Bulleid Pacific ran with a Black 5 tender due I believe to Southern loco's not having water scoops
     
  2. Martin Perry

    Martin Perry Nat Pres stalwart Staff Member Moderator Friend

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    Usually a solid bar with a pin through each end into the dragboxes.
    Generally smaller side bars additionally.
     
  3. Jamessquared

    Jamessquared Nat Pres stalwart

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    There's no doubt lots that could be said about compatibility, heights etc, but for illustration here is 75027 (BR STd 4) split apart.

    On the loco you've got a sprung draw hook to take loads in tension (i.e. when the loco is hauling the tender). Either side are two buffing plates for loads in compression (i.e. when the loco is pushing the tender e.g. running in reverse). The two chains below are safety chains, which are normally slack but are designed to hold the engine and tender together of the drawbar fails. Then you've got vacuum, steam heat and water feed connections.

    On the tender, you've got a slot where the drawbar goes (and is secured), two buffers, and the same vacuum, steam heat and water connections.

    The BR standard tenders are a bit different to others, in that the entire footplate is part of the cab on the engine. On most older engines, the footplate is split, with half on the engine and half on the tender, with a hinged fall plate to bridge the gap and stop you falling in between.

    IMG_4807.jpeg

    IMG_4806.jpeg

    Tom
     
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  4. RLinkinS

    RLinkinS Member

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    The Southern moguls had a large spring surrounding the draw bar to keep the coupling bar tight. The tender and loco must have been pushed together in order to insert the coupling pin
     
  5. Martin Perry

    Martin Perry Nat Pres stalwart Staff Member Moderator Friend

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  6. Jamessquared

    Jamessquared Nat Pres stalwart

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    This is the tender on the O1, with drawbar, smaller draw links (rather than the safety chains) and two small buffers. You can also see the hinged fall plate on a more traditional tender design.

    IMG_2748.jpeg

    Tom
     
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  7. Monkey Magic

    Monkey Magic Part of the furniture

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    And the LMS engines when working on the SR ran with Austerity tenders.

    [​IMG]

    [​IMG]


    Which raises a question, as you say the Bulleid's ran with Stanier tenders so why the austerity tenders and not Bulleid tenders? Strange that a Bulleid loco can run with a Stanier tender, but Bulleid tenders didn't run with Stanier locos.

    (I am sure that there is a very mundane answer).

    Odd seeing the engines with BR numbers and tenders lettered LMS...
     
    Last edited: Jan 26, 2022
  8. Jamessquared

    Jamessquared Nat Pres stalwart

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    I suspect it was as mundane as availability - giving the LMS locos a Bulleid tender during the trials would have taken a Bulleid pacific out of traffic for the duration (including the time to set up etc) My hunch is that the Austerity tenders were more available / less consequence from borrowing one.

    Wasn’t one of the tenders used a self-weighing one? Or did I imagine that?

    Tom
     
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  9. LMS2968

    LMS2968 Part of the furniture

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    The reason the Bulleids got Stanier tenders was to give them water scoops over the other regions; there were no troughs on the Southern so his tenders weren't so fitted. Neither were WD tenders, but they did have 5000gallon water capacity, which the LMS engines needed on the Southern.

    The combination of BR number and LMS lettering was quite common until well into the 1950s.
     
  10. Monkey Magic

    Monkey Magic Part of the furniture

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    I know why the Southern locos got LMS tenders. What I am curious about is why the LMS locos didn't take Southern tenders.

    I am assuming that the austerity tenders were especially lettered up as LMS.

    The Southern locos with LMS tenders were lettered up with British Railways

    [​IMG]

    @Jamessquared - availability does seem to make the most sense as the Bulleid's appear to have run with the LMS tenders during the whole trials including on the Southern(?). The cynic would joke that in the late 1940s it would be unusual for there not to be spare Bulleid tenders around considering issues of reliability.

    [​IMG]

    But this then raises another question. If the LMS locos couldn't run on the Southern with Stanier tenders because of water capacity, how could Bulleid's run on the Southern with Stanier tenders? (I am assuming it was probably not hauling the ACE when paired and if hauling trains that were stopping within water capacity)

    For anyone interested - there are lots of photos of the trials on the Nine Elms site

    https://svsfilm.com/nineelms/coffin.htm

    https://www.svsfilm.com/nineelms/exchange.htm

    There is this interesting account of the effects of swapping a Stanier tender for a Bulleid:

     
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  11. LMS2968

    LMS2968 Part of the furniture

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    There probably were compatibility issues between the LMS cabs and Bulleid tenders, particularly the overhang of the roof. The LMS did have some of the WD tenders available so any necessary modifications were easily made. One modification was to paint the tenders with LMS on the tender tank rather than BRITISH RAILWAYS. Possibly someone had a point to make?

    The Stanier tenders were taken from six 8F 2-8-0s, and these too ran with WD tenders in the interim. These were 8396; 8492; 8602; 8647; 8670; 8687. All received the own tenders back, 8670 being the last in September 1948.
     
  12. MellishR

    MellishR Resident of Nat Pres Friend

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    This seems as good a place as any to enquire about the safety chains. I've always wondered whether, in the rare even of the main drawbar breaking, the chains would actually withstand what could be a violent snatch when they became taut.
     
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  13. johnofwessex

    johnofwessex Resident of Nat Pres

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    There was an incident when the drawbar broke on a Britannia - certainly the chains didnt work on that occasion.
     
  14. Musket The Dog

    Musket The Dog New Member

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    Just a thought out loud on safety chains, would tenders have brakes that come on automatically if seperated from the loco, if they weren't just hand brakes? While it's much more likely that the chains would give way with a heavy train on the rear, but then at least the tender is then still attached to the remaining braking capacity of the train.

    My thought is that the more dangerous situation would be a drawbar giving way on an engine travelling light without the chains, leaving a seperated tender with no means of putting the brakes on. The chains might just be meaty enough to prevent that situation?
     
  15. LMS2968

    LMS2968 Part of the furniture

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    Generally, there would be no power brake on either engine or tender in the event of a breakaway when running light, although I doubt that the chances of such a breakaway in those circumstances were very probable.
     
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  16. bluetrain

    bluetrain Well-Known Member

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    Interesting to see the tender swapping for the 1948 trials. Given that Riddles was in charge of the WD designs, I assume that he used standard LMS drawgear for the WD tenders?

    The LNER often exchanged tenders between LNER standard types and those inherited from the LNER's main English constituents (GN/GC/GE/NE). Several Gresley loco classes had a mix of GN and LNE standard tenders, while B17s ended up with a mix of GE-type, ex-NE and LNE standard, and the D49s with a mix of ex-GC, ex-NE and LNE standard. Which implies that the GN, GC, GE & NE all used tender drawgear that was compatible (or could easily be made compatible). Elsewhere, ex-ROD tenders of GC design were re-used with GW engines and with LNW Claughtons, implying compatibility.

    But I've not come across any examples of ex-NB and ex-GNS tenders being used with other LNER engines, nor of ex-NB & ex-GNS engines being paired with "foreign" tenders. It seems that Scottish tenders stayed with Scottish engines.

    Apart from drawgear compatibility, another factor that could limit tender interchangeability was compatibility of braking systems. Apart from two systems being in use for train braking, the (power) brakes on the engines themselves could be steam, air or vacuum. This gave rise to numerous combinations of engine brakes and train brakes, but tenders on the LNER and its constituents appear always to have had the same braking system as the engine, so steam-braked engine had steam-braked tender, vacuum-braked engine had vacuum-braked tender,etc. Whereas I believe the Southern had some steam-braked engines with vacuum-braked tenders.
     
  17. Bill2

    Bill2 New Member

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    A minor issue with steam brakes the diameter of the tender brake cylinder should accord with the boiler pressure, so for example when the WD tenders (bp225 psi) were attached to Duchesses or Royal Scots in 1948 (bp 250 psi) the diameter of the brake cylinder should have been reduced, not sure whether it was. The comment in a previous post about losing the brakes if the loco and tender part only apply with the steam brakes on both loco and tender, with vacuum a full application would take place.
     
  18. 32110

    32110 Member

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    BR locos I think were fitted with a valve to isolate the steam supply to the tender for this very reason.
     
  19. used2be

    used2be New Member

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    So how come there were all these spare WD tenders available when the exchanges took place ?
     
  20. LMS2968

    LMS2968 Part of the furniture

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    Possibly for the same reason there were so many ROD 2-8-0s at the end of the First World War.
     
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