Walsworth Models Sentinel Y1 8400

Discussion in 'Workbenches, including workshop techniques.' started by Sandy Harper, 9 November 2017.

  1. Sandy Harper

    Sandy Harper Western Thunderer

    And now for a bit of light relief after the trauma of the A3!

    This is what you get in the box. Only solder, flux and paint required. 103_4457.JPG

    Two hours last evening saw the chassis almost complete apart from the brakes and guard irons. No special jigs required just an engineers square and a flat surface.




    Another two hours this morning had the brakes attached , guard irons fitted and the one piece footplate etch folded and soldered.


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  2. adrian

    adrian Flying Squad

    That looks a nice little project - I really do like the Sentinels.

    So it appears in the kit you get the prototypical chain drive to drive both axles. :thumbs: It's a shame they didn't go the whole nine yards and have the motor and gearbox driving an idler shaft and make the final drive to the axle a chain drive as well. :rolleyes:

    Hopefully you haven't got round to the axle box yet as it appears from the photo that the wrong type are supplied. You may well decide to fit the axle boxes as supplied but as a Sentinel anorak they look wrong to me. It's the torsion bar.

    As far as I'm aware on the Y1/Y3 the axle box torsion bars meet in the middle

    Screen Shot 2017-11-09 at 18.37.39.png

    from Sentinel Steam Loco 7109: 100HP Pre-war Sentinel Locos

    Whereas the larger 200hp models (like the S&D model) from Walsworth have beefier spring hangers and the torsion bar attaches to these hangers.

    Screen Shot 2017-11-09 at 18.44.18.png

    from Sentinel Steam Loco 7109: 200HP Pre-war Sentinel Locos (1)

    From your photo it appears the latter version is in the kit rather than the former.
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  3. Overseer

    Overseer Western Thunderer


    I would have agreed with you but looking at my copy of the 1927 Sentinel catalogue it looks like the kit is correct for a very small number of early prototype CE locos, see below. Note the curve in the sheet metal between the cab and 'bunker' which the etch has but the later standard CE locos didn't and no external straps which do appear on the etch (but were on some locos including the similar but longer wheelbase LMS NCC no. 91, which had the suspension link as provided in the kit).
    Sentinel early CE 1927.jpg

    This is the standard version of the suspension for the production pre-war CE Sentinels as described by Adrian -
    sentinel 1927 suspension.jpg

    Someone with the relevant Yeadons Register to hand will be able to tell us which Y1 locos were which version.
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  4. oldravendale

    oldravendale Western Thunderer

    Correct or incorrect in detail here's one I made earlier from the same kit. Outstanding value for money! From memory the only changes I made were to fit a rocking axle and to scratch build the injectors. Pick up is very reliable and it's pulling power is out of proportion to its size.

  5. adrian

    adrian Flying Squad

    That looks great and I am seriously tempted by one but is that not the Y3 kit? There are a number of differences to the etches Sandy has posted, the chassis rails are deep along the full length, no curve in the plate work above the British Railways and the window is in a different position.

    A good spot on the radius - I hadn't clocked that. However the very early CE engine has a curved beading around the top of the door opening and a large window. The etchings shown have a straight door opening and small window. I can't find any photos of any loco with all of these details present. I suspect it was based on either an export or industrial CE engine not the ones designated by the LNER as Y1. As always with these things a good photograph to work from is worth it's weight in gold.
  6. adrian

    adrian Flying Squad

    Small correction - I have found a photo to match the body work details although I can't make out axle box arrangement from this photo. The shape of the chassis rails matches the etches.

    It seems that the etches are specifically for the Y1 prototype 8400, which differs slightly as discussed from the production Y1.



    c.1933 - Lowestoft.
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  7. Steph Dale

    Steph Dale Western Thunderer

  8. Overseer

    Overseer Western Thunderer

    A little more research reveals the kit as shown by Sandy is also correct for the Derwent Valley Light Railway loco, Sentinel 6076 of April 1926. LNER Y1/1 number 8400 was Sentinel 6170 of September 1925.
    Sentinel DVLR 6076.jpg

    The catalogue illustration shown earlier is the first CE type locomotive, Sentinel 5733 of June 1925 sold to Leys Malleable Castings. All Sentinel locos and railcars before this had horizontal engines.
    Sentinel Leys 5733.jpg

    There were probably other locos matching LNER 8400 but photos would be needed to confirm it. The builders numbers and dates are quite jumbled through 1925 and 1926. It seems Sentinel were building locos on spec and changing the build date when they completed them for sale. Vertical Boiler Locomotives and Railmotors Built in Great Britain by Rowland A.S. Abbott has the full Sentinel works list.
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  9. adrian

    adrian Flying Squad

    Cheers - yes that helps. the torsion bar is attached to the spring hangers as per the castings in Sandys photo.
  10. adrian

    adrian Flying Squad

    I wouldn't be so sure on other matching ones, the cab beading and the window size and position differs on the LEYS loco. I think everyone was built on spec with minor variations depending on the customer. I have a copy of "An album of Sentinel works photographs No. 2 DG, S, Diesel& Rail" by Anthony Thomas and this has a full list of locos and customers unfortunately the lists don't have sufficient details for all these subtle variations.
  11. Sandy Harper

    Sandy Harper Western Thunderer

    Gents my apologies. I should have described it as the Y1 8400. Sorry for the confusion.

  12. oldravendale

    oldravendale Western Thunderer

    You are quite correct, Adrian. I'd not checked the kit which is the subject of this thread properly, and didn't know that Walsworth did a Y1 and a Y3. Here's a photo of the propotype 8400 followed by a full description by Mike Bootman of the GER Society to whom I remain indebted for the amount of work he did on identifying both loco and confirming the location.


    8400 LNER Y1 Class.    FINAL 1000 dpi Copy.jpg

    8400 LNER Y1 Class Sentinel. Date approx 1935. Lowestoft Harbour. Notes by Mike Bootman follow: Lowestoft Harbour - alongside the Trawl Dock with Waveney Road in the background. The Eastern Counties Railway and later the Great Eastern Railway undertook a considerable amount of development and expansion of the Harbour and consequently it was well served by rail. As well as serving the Outer Harbour Trawl, Waveney and Hamilton Docks on the north side, at the easternmost extremity of the outer wall there was a sand extraction plant. There were also comprehensive sidings to private works and factories on the south quay of the Inner Habour, together with the railway's own Yards, Works and Sleeper depot n the North Quay. Class Y1 Sentinel CE (Central Engined) Loco No. 8400 (first of the type) shunting GWR wagons on quayside. The locomotive is the first member of Class Y1 Sentinel CE (Central Engined) Loco No 8400. It was the first of the type purchased from Sentinel in 1925 for evaluation, the LNER having in May 1925 tested a similar one on the Derwent Valley Railway using it's Dynamometer Car. Sentinel claimed that this design used less than half the coal and water, and cost less than half the amount to maintain and repair than a conventional locomotive. Furthermore it's short wheelbase and light axle loading permitted its use on sharply curved and lightly laid lines. The locomotive was delivered to Lowestoft in September 1925. Following its first six months operation it was estimated that it saved £158 (£316 per annum) compared to a conventional steam locomotive and, at a purchase cost of £1400 this was clearly a very good return on the investment. Consequently the LNER purchased a number more of two different types (and vatrious sub-types) classed as Y1 and Y3. The profile of this locomotive, originally numbered 8400 on taking into stock at Lowestoft on 27/9/1925, was different to all of the following ones in that it was taller, had a radiused sheet metal fillet on either side between cab front and tank top, different frames and various other elements which make it readily identifiable from the others. It is just possible to make out the No. 8400 on the lower cab side. It spent the whole of its working life at Lowestoft, being renumbered 7772 on 1/4/1943, 8130 on 12/1/1947, and finally Departmental No. 37 on 26/4/1953 before being condemned on 31/1/1956. At some unknown date, before the photograph was taken, the short handrails either side of the cab were extended downwards. It is just possible to see the location of the original fixing mid-way between the running plate and the beading level with the tank top. It travelled to Stratford just the once for a General Repair, between 19/12/1936 and 21/3/1937, thus supporting the manufacturer's claims of economy. Its main duties were in and around the Sleeper Works but also involved trips to the North Harbour area, where it is seen in this photo heading alongside Wveney Road towards the Fish Docks. Given the lack of interchange traffic with the GWR it's interesting to note that the goods wagons it is hauling are all, bar one, clearly marked with that company's ownership. The van beyond on an adjacent line is an ex-GCR 10T 18' Fish Van, which is coupled to an early LNER design 10T Fish Van just visible behind the Y1.
    Personal collection. Photo by the late Arthur Dudley Neg ID No 40. FINAL
  13. adrian

    adrian Flying Squad

    No need for an apology at all - it's us polluting your thread and confusing the issue. I've learnt something so I'm grateful for your posting.
  14. oldravendale

    oldravendale Western Thunderer

    Yes, Adrian is absolutely on the button. Sorry for creating confusion, but I hope the photo and details helps to make up for it.:oops:

  15. simond

    simond Western Thunderer

    Er, being picky, I suspect it’s not strictly a torsion bar as it appears to be pivoted at both ends - which means it could not prevent the axlebox twisting about the axis of the axle. Some twist in the axis of the bar would also be necessary if wind in the track forced to axles out of parallel in the end view.

    Its function appears to be to prevent the axle moving fore or aft under tractive/braking forces, and reacting the chain tension, which the leaf spring probably isn’t at all good at. As I understand it, the loco does not have W irons or hornguides, except possibly a narrow vertical bar above the axlebox, so something would be required to react these forces to the frame - and, of course, to maintain the chain tension.

    Indeed, the radial nature of the bar, more or less parallel to the chain run, may compensate for suspension movement whilst maintaining the chain run at a sensible length rather better than vertical axle movements in horns would.

    Does this make sense?
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  16. Steph Dale

    Steph Dale Western Thunderer


    You're on the money, my belief was that they were effectively the chain tensioners.

  17. adrian

    adrian Flying Squad

    I suspect you’re correct, however for the want of a better word torsion bar was the best I could muster at the time.
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  18. Sandy Harper

    Sandy Harper Western Thunderer

    Basic body work erected today. I have also added some scrap etch to deepen the valance, extended the cab handrails and 'clipped ' the buffer beam corners as per the excellent photograph of 8400 as it was later in its life.. DSCN3658.JPG


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  19. adrian

    adrian Flying Squad

    That's looking good - the deeper valance does make a big difference to the look of the model.:thumbs:
  20. Overseer

    Overseer Western Thunderer

    Maybe I should have included the written description with the cutaway suspension drawing - Sentinel called them radius rods. The springs were not fixed to the frames at all so the wheelbase could be varied to take up slack in the chains. The axle illustration shown below has short radius rods so must be from one of the early locos.
    Sentinel 1927 radius.jpg

    I am glad Sandy wasn't too clear about the prototype as it has brought up some really good photos and given us a chance to look a bit more closely at the earlier Sentinel locos. The 1938 colour photo found by Steph is amazing. The prominence of the red lining is striking as it doesn't show up well in black and white photos. The orange colour of the buffer beams is also noteworthy, model paint for buffer beam red seems to have been getting redder over the last few decades. But it is the LMS five plank wagon that has made me wonder - it looks like it is in 1936 Bauxite livery from a few small flecks visible but where has it been to become so black in only two years or so?
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