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Sir Nigel Gresley - The L.N.E.R.’s First C.M.E.

Discussion in 'Steam Traction' started by S.A.C. Martin, Dec 3, 2021.

  1. Sheffield

    Sheffield New Member

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    I think you underestimate the value of the people who worked under the CMEs you mention. The Duchess was really Colman's work, but without Stanier would have not been produced. A good boss will encourage encourage and draw out from his men, while a poor boss will stifle them. I suggest this was one area where Churchward was very good, and Bullied less so, for example.
     
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  2. MellishR

    MellishR Resident of Nat Pres Friend

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    Can you tell us more? Why did they build two sets and not put either of them into service? And what became of the DMU?
     
  3. weltrol

    weltrol Part of the furniture Friend

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    https://en.wikipedia.org/wiki/LMS_railcars :
    Articulated unit
    LMS 80000–80002
    [​IMG]
    Railcar 80002 as built in 1938, official photograph.
    In service 1939
    Manufacturer London, Midland and Scottish Railway
    Built at Derby Carriage and Wagon Works
    Constructed 1938
    Number built 1 set (3 cars)
    Number scrapped All
    Fleet numbers 80000–80002
    Capacity 24 first-class
    138 third-class
    Operator(s) London, Midland and Scottish Railway
    Depot(s) Bedford
    Specifications
    Train length
    182 ft 0 in (55.47 m)
    Car length Centre: 52 ft 0 in (15.85 m),
    Outer:64 ft 0 in (19.51 m)
    Articulated sections Three
    Weight 73 long tons (74 t; 82 short tons)
    Prime mover(s) Six 125 hp (93 kW) engines (2 per car)
    Power output 750 hp (559 kW)
    UIC classification 1A+AA+AA+A1
    Track gauge 4 ft 8+1⁄2 in (1,435 mm)
    In 1937, the LMS decided to produce a more modern diesel train for itself. This was a three-car articulated railcar built to LMS diagram D1996 and outshopped from Derby Carriage and Wagon Works in 1939. The cars were numbered 80000, 80001 and 80002.[2]

    The streamlined three-car train was a single articulated unit; the two outer coaches were each 64 ft (19.51 m) long and rested on a centre coach that was 52 ft (15.85 m) long. The articulation was an idea that had been already taken up by Sir William Stanier for some locomotive hauled stock.

    Mechanically, the train was a development of railcars that had entered service from 1933 on the LMS Northern Counties Committee's (NCC) lines in Northern Ireland, using an identical arrangement of in-line powertrain as NCC railcars Nos. 2–4. Under each coach were two vertically mounted Leyland 125 bhp (93 kW) diesel engines driving the inner axle of each bogie through a Lysholm-Smith torque converter. There were six engines for the three-car set which gave a total power of 750 bhp (559 kW). The whole unit weighed 73 long tons, so this yielded a power/weight ratio of slightly more than 10 bhp/ton which provided a main line standard of performance with a maximum speed of 75 mph (121 km/h).

    Accommodation in the end cars was split into two saloons with 26 seats in the outer saloon plus a lavatory, and 28 seats in the inner saloon, all seats being reversible and third class. Between the outer saloon and the driving cab was a small luggage and brake compartment. The centre car was a composite with a 30-seat third class saloon with a lavatory, and the other saloon having 24 first-class seats. All of the seats were arranged as 2+2. The cab was generously proportioned with the driver in a central position.[2]

    It entered revenue-earning service in 1939 based at Bedford,[2] and worked first on the Varsity Line between Oxford Rewley Road and Cambridge, and then on St PancrasNottingham services.[citation needed]

    A second unit may have been intended, and the diagram was marked that two units should be constructed although the order was for the one unit that was actually built. 80000–80001–80002 was withdrawn on the outbreak of World War II in 1939, stored, and never re-entered passenger service.[2]

    Conversion for Overhead line maintenance
    In 1949, British Railways converted the articulated unit to a two-car set for overhead line maintenance. The centre car was removed and the number of engines in the set reduced to two. The driving cabs were given flat ends. To enable engineering staff to work on the overhead cables the roofs of the two coaches were flattened, creating a work space 130 feet (40 m) long and 5 feet 4 inches (1.63 m) wide. Between the two cars a manually-operated lift was installed that could be raised to 6 feet (1.8 m) above roof level.[3]

    One coach was converted into a workshop with all passenger seats removed and workbench facilities installed. The other coach was converted into staff accommodation with lockers, cooking, washing facilities and a WC, and 12 seats with tables as a mess saloon.[3] An old 30 feet (9.1 m) coach was converted to carry 2,000 feet (610 m) of overhead wire and attached to the unit as a trailer. Portable floodlights for night work were installed in the two coaches and in the trailer.[4]

    The unit worked on the Manchester – Altrincham line. It was moved to Longsight Depot in 1959 and taken out of service shortly afterwards. It still existed in a derelict state as late as 1967.

    The design may be seen as a step in the development of post-war British Railways diesel multiple units (DMU) such as the Derby Lightweight units, at least as far the powertrain is concerned.
     
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  4. bluetrain

    bluetrain Well-Known Member

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    The above post stresses an important theme - that Gresley was a thinker, innovator and experimenter throughout his career. Of course, those are not the sole requirements for a CME, but they do mark out Gresley from most of his contemporaries. Among British CMEs of the Grouping-era, Bulleid seems the only one to exhibit those attributes to a similar degree.

    Soon after Gresley succeeded Ivatt on the GNR, he introduced 2-6-0 and 2-8-0 designs that were markedly different to previous GNR practice. Then in 1918, he built his first 3-cylinder loco, 2-8-0 No 461. Although Robert Stephenson had built a 3-cylinder loco as early as 1846, such machines remained extremely rare for many decades (and in most countries, remained rare or unknown until the end of steam). In 1918, only two other railways had started to build 3-cylinder non-compound locos in significant numbers - the North Eastern Rly from 1909 and the Prussian State Rly from 1914. Given wartime impediments to information flow, Gresley may have been unaware at the time of the German 3-cylinder developments. (Prussian 4-6-0 & 2-10-0 designs, plus Saxon 3-cylinder 4-6-2).

    I think it is fair to view Gresley as the most consistent advocate of 3-cylinder locomotives for the rest of his life, not just in Britain but globally. Although German 2-10-0s came to be the most numerous 3-cylinder engines, Gresley introduced a greater number and variety of 3-cylinder classes than the Reichsbahn. In addition to Gresley's 3-cylinder designs, there were also of course those inherited by the LNER from the NER & GCR, plus those later introduced by Thompson and Peppercorn.

    Did anyone ever write a book on the specific topic of 3-cylinder locomotives? I cannot recall one, but I'm sure that Simon's Gresley book will have comments to make about the pros and cons of the 3-cylinder design option.
     
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  5. Bill2

    Bill2 New Member

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    At risk of some thread drift, but to carry on the story of the LMS Coronation Scot as mainly told by David Jenkinson in his book on LMS coaches. The LMS decided to build a new Coronation Scot train for the American visit in 1939, though in fact what was sent was not a complete set but with a couple of additional coaches, one of which was a sleeping car for the staff. The intention was then to complete the set and introduce it into service in 1940, but it would not be practical to do this and mix it with the existing sets as the accommodation was different so they decided to build the two further sets as well. Construction started but was then held in abeyance "for the duration", and the 1939 set was stuck in America at this time in any case.
    Towards the end of the war, construction of the new stock and that to complete the 1939 set was started again, and reading the memoranda from R.C. Bond quoted in Jenkinson's book, he seemed to be aiming to have the vehicles completed in 1946 though it actually it took longer than this. Anyway the American set was brought back and the three sets completed but not put into a postwar Coronation Scot, or indeed put into service as sets at all.
    To answer the specific question; why the Coronation Scot was not reintroduced is not particularly clear, though presumably for the same reason that the LNER did not reintroduce their streamlined trains in that speeds were restricted so they could not justify charging a supplement and the limited accommodation meant that the service would be unprofitable without the supplement and was probably unsuitable for the business on offer at the time in any case. The LMS (and later BR) then had the difficulty of finding a use for these rather specialised coaches non-standard with other stock, one problem being that the brake ends had been build without end gangway connections. The sets were split up; Jenkinson does not give a complete history (possibly it hasn't survived) but quotes uses for some of the vehicles, and suggests that one or two never turned a wheel in revenue service.
     
  6. S.A.C. Martin

    S.A.C. Martin Part of the furniture

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    No worries about thread drift. All in good fun!

    It is true the streamlined trains did not reappear - however the vehicles were used by the LNER and then BR in everyday service, some of the vehicles cascaded into replacing older vehicles in some sets. The valances were removed on the articulated coaches and the observation coaches and all were eventually put into blood/custard livery. When they went into maroon, the observation coaches were substantially rebuilt.

    So, the streamlined named trains didn't re-emerge. But the vehicles were still used.
     
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  7. maddog

    maddog New Member

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    I'm surprised it took pretty much until the Mk3 coaches for Valances to appear again, seems like would have provided some benefit and with access hatches or cut outs to be little different to the boxes underneath in terms of maintenance? I suppose the added weight vs presumably marginal gain plays a part? I say this as someone completely clueless as to carriage maintenance requirements.
     
  8. S.A.C. Martin

    S.A.C. Martin Part of the furniture

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    So the wind tunnel tests by Johannsen suggest streamlining the entire train made a very significant difference to the fuel economies of high speed trains.

    Today’s aerodynamics for trains show that what we describe as streamlining in the 20s/30s has now evolved into a very scientific and in depth fluid mechanics field that means virtually all new trains are subject to wind tunnel testing, both actual and theoretical by way of computer modelling.

    Making rail vehicles more aerodynamic brings gains, but you have to treat the train as one unit, which is what the W1 didn’t do well on, but the A4 plus the streamlined trains did. But the W1 was the first so obviously wasn’t going to be perfect as the first attempt.
     
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  9. Jamessquared

    Jamessquared Nat Pres stalwart

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    There's also a square law relationship with speed - my hunch is that it was simply not worth the effort and cost and operational complexity of streamlining whole trains when most of the time those trains were rarely going above 80-odd mph. It really only became worth streamlining whole trains when running speeds frequently were in the 100+ mph range for long sections at a time. And that in turn simply wasn't possible when the "streamliners" had to share tracks with many much slower services. The benefit of a given shape is, for example, more than 75% greater at 100mph than at 75mph; in other words, streamlining that is significant at 100mph is actually rather inconsequential over the vast majority of the loco’s duty cycle when it is running much slower.

    As an aside - my understanding is that to enable the high speed expresses, the LNER had to clear the tracks for a considerable period ahead so as to avoid the express catching up - and thereby being delayed - by a slower train. One wonders quite where the passenger value was in that service, if you were at an intermediate station and had a delay of an hour or so, just to see a train rush by at high speed that you couldn't catch!

    My gut feeling is that in this country, streamlining only really came into its own with the IC125, which was the complete package: high speed train, rapid acceleration and braking so it spent most of its run at high speed, and a timetable designed around those trains.

    Tom
     
    Last edited: Mar 27, 2023
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  10. johnofwessex

    johnofwessex Resident of Nat Pres

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    Not only that but by the time they were introduced the unbraked freight train was on the way out and the vast majority of fast services between Bristol and Paddington were in the hands of IC125's so thety wernt having to be threaded through slower trains.
     
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  11. Jamessquared

    Jamessquared Nat Pres stalwart

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    Quite.

    Tom
     
  12. 35B

    35B Nat Pres stalwart

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    That doesn't explain the profiling of the GWR railcars of the period, which did incorporate what appears to be streamlining, yet rarely if ever reached the speeds necessary under that analysis.
     
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  13. huochemi

    huochemi Part of the furniture

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    From the LNER 1937 "Review of the Company's Business".
    review of 1937_high_speed_services.jpg
     
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  14. Jamessquared

    Jamessquared Nat Pres stalwart

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    Edit: see @Jimc later comment.

    Tom
     
    Last edited: Mar 27, 2023
  15. 8126

    8126 Member

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    Because it looked good to contemporary aesthetic tastes and didn't cost much more than doing a convential coach end? Also, with double-ended single cars, you don't have to deal with what I might call the Class 90 problem in which a streamlined rear end on a locomotive coupled to a train simply serves to increase the drag on the first coach.

    This is correct, but also it's worth remembering that the power requirement for overcoming aerodynamic drag goes with the cube of speed. Because your drag force goes with speed squared, and power is force x velocity, your power requirement to overcome drag is 137% greater (or multiply by 2.37, to arithmetic taste) at 100 mph than 75 mph. And since power tends to be the limiting factor on speed, either in terms of how many horses you've crammed into the engine or how fast your fireman can shovel coal, the advantage of streamlining and reducing that power requirement by even 25% should be very apparent once you get to consistent 100mph+ speeds.
     
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  16. S.A.C. Martin

    S.A.C. Martin Part of the furniture

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    I think there’s a strange misconception going around here.

    Aerodynamics affect vehicles at all speeds.

    If it wasn’t worth making vehicles aerodynamic because they don’t go often above 80mph, we wouldn’t bother doing any kind of wind tunnel testing or fluid dynamics testing with cars that generally about town are meant to do 30mph and below.

    The saving in horsepower and fuel increases as speeds increase. Just because something gives a smaller gain at 30mph than 80mph doesn’t mean you shouldn’t do it.

    If your streamlined train is doing 0-30mph in acceleration then and a constant 30mph for 50 miles, your streamlined train has provided a better fuel economy than a conventional one and likely greater acceleration to 30mph.

    Not true Tom, sorry. I think you need to review what the LNER achieved because it was truly phenomenal.

    The LNER streamlined trains heralded an improved braking system for the whole train (hence the braking tests that Westinghouse were associated with, and on the train when Mallard broke the record).

    The timetable for the LNER high speed trains required double blocks in the signalling in the early days, until the improved braking was in place, because of the high speeds and tight schedule they were working to.

    The LNER upgraded the signalling to colour light signals on many stretches of track where the high speed trains would run - see attached, the Coronation at Ganwick Curve.

    4F9EA221-455B-43AC-AA36-1C4449A167BD.jpeg

    The permanent way prior to the Second World War was being steadily updated, and had the war not occurred, all of the different factors were in place to make the LNER the world’s foremost high speed railway.

    The next stage would have been electrification, seriously considered, and debated, for decades.

    Gresley was by far ahead of his time.
     
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  17. 8126

    8126 Member

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    And yet even today the vast proportion of suburban electrics have front ends not significantly more obviously aerodynamic than say, a Crab. Yes, aerodynamics apply at all speeds. But mass really applies at all speeds (and extremely so once you get fast enough, but that's outside the scope of this piece), and for something like a suburban electric capacity is king, followed by acceleration and then probably flexibility, even if they'll run up close to 100mph. Front end shapes are all very well, but you can't make a corridor connection through them and you can't fit in an extra row of seats. Some of them even have recessed doors, for shame! All a long way from close-coupled articulated sets with sheeting between the vehicle ends to clean them up.

    Basically, although railways are a very efficient way of moving large masses around, at moderate speeds the loads involved with doing that are still sufficiently high as a proportion of the total to make aero improvements a nice-to-have rather than essential.
     
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  18. 30567

    30567 Part of the furniture Friend

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    It would be interesting to see the train planning graph for the ECML in 1937. My guesses are (a) utilisation was a lot less intensive, (b) there was a lot more flexibility overall, though certain places like Wood Green to Potters Bar were notorious exceptions, (c) there was a big mix of traffic speeds on the line and many conflicts, (d) intermediate places like Peterborough and Newark were relatively less important sources of traffic than today, (e) many sums must have been done to assess the trade offs referred to in the quote above-- a few super expresses manageable, a lot not manageable.

    Of course they didn't need 34 A4s to run the Silver Jubilee and the West Riding!!
     
  19. S.A.C. Martin

    S.A.C. Martin Part of the furniture

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    Sorry, what?

    That clearly isn’t true.

    7398CBFC-CA6B-4D34-8184-86DE3880C47F.jpeg

    This book (which was recommended reading for my apprenticeship at the high speed rail college) suggests you don’t understand aerodynamics.

    Many of the slow speed high capacity trains you are talking about have lower coefficients of drag than you are expecting, I think!

    A5AA7E90-5B40-4C1E-A676-3FA153999537.jpeg

    I think I’ll leave it for the book to argue about aerodynamics, it’s a bit exhausting thinking about responding tbh.
     
  20. 8126

    8126 Member

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    I know a reasonable amount about aero. And the critical thing about those low speed trains (plus the Class 47 and 5 coaches which is mysteriously rather better than an IC225) is that they're short. I'm assuming those drag coefficients are based on frontal area rather than wetted area?

    As a follow up edit, thank you for the numbers:

    Based on a crude universal assumption of a 10m^2 front end, an IC225 is putting 1600ish hp into aerodynamic drag at 50 m/s (111 mph) and 100hp at 20 m/s (45 mph). Scale up to 161 mph (the highest speed one ever did) and you're at 4900hp in drag alone, out of 6300 total available, which goes to show why aero really matters at those speeds. Dropping an extra 10% would be fantastic - 490 hp.

    A 2-car class 165 would need 25 hp at 20m/s and 400hp at 50 m/s (for which they are not rated). Scale for length (multiply everything by 5) and it's about 25% worse than the IC225, even with quite a nice nose by EMU standards. But they have 700 hp and at maximum permitted speed they're using 213 hp for aero. How much effort do you go to in order to achieve a 20% improvement in those numbers and reduce the total horsepower requirement at 45 mph by 5 hp? Clearly the law of diminishing returns applies and things like aerodynamic noses, fairings between coaches and valances between the bogies are a bit of a luxury once you're not dealing with something as aerodynamically dirty as a steam locomotive and you're still only dealing with suburban speeds.

    And steam locomotives are very dirty (yes, I cited the Crab as hyperbole). Mr Johansen's tables (posted earlier) suggest a drag coefficient for 4472 and tender of 1.87, presumably with a train behind but the force only measured on loco and tender. It's basically an 8-car 319 set on its own; you might assume double the drag coefficient for a complete train. But also you might not; the much dirtier air and wide wake left by the loco can reduce the drag on the coaches immediately behind (see racing cars and getting a tow, plus Royal Scot tenders). Aero can be tricky like that, especially at the back of long things where a sharp separation from a chopped off tail can be just as good or better than a carefully faired in beavertail (aerofoils aren't like that because we like lift).
     
    Last edited: Mar 27, 2023

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