LMS 4-6-0 Locomotives in Great_Britain


Class Details by Steve Llanso of Sweat House Media

Class 5XP Jubilee (Locobase 3071)

Data from Edward Cecil Poultney, British Express Locomotive Development (London: George Allen and Unwin, 1952), p. 173; LMS diagram in "Three-Cylinder 4-6-0 Passenger Tender Engines', LMS Magazine (July 1934) archived at []; and "6P5F & 7P 45552 - 45742 4-6-0 LMS Stanier Jubilee" on the Preserved British Steam Locomotives website at [], last accessed 21 May 2023. See also "The Jubilee Locomotives of the LMS" website at [], last accessed 21 May 2023.

As delivered, these express engines by William Stanier were disappointing, being a little short of breath. This was primarily due to the undersized 14-element superheater, which contributed only 228 sq ft (21.19 sq m) to the total (a stingy 12.4%). Among the first changes to try to remedy the defects were made to the blastpipe (reducing the diameter from 5 1/4" / 133 mm to 4 7/8"/ 123 mm) and the stack (removing the jumper top) and these sharpened the draft and improved the engine.

Of much greater importance was the fitting of 24-element superheaters in place of the inadequate 14-element superheaters with which the class originally was delivered. At the same time, the grate was enlarged slightly from 29.5 sq ft (2.74 sq m) to 31 sq ft (2.88 sq m). These changes raised the firebox heating surface from 162 sq ft (15.06 sq m) to 181 sq ft (16.83 sq m). The reader can see that even with the enlargements, the boiler was pressed hard to feed three cylinders through their relatively capacious 9" (229 mm) piston valves.

Eleven were later refitted with a sloping throatplate boiler (5567, 5590, 6607-08, 5610, 5616, 5621, 5622, 5639-40, 5657 and 5665-5742 were delivered with that design. The slope reduced the tube length from 14 ft 3 in to 13 ft 3 in.

Two were subjected to significant changes to the Belpaire boiler and firegrate in 1942 -- see Locobase 3760.

[], accessed 12 August 2007, reproduces a table from Atkins, P. West coast 4-6-0s at work. 1981. Chap. 8 that compares the original Jubilees to the Patriots and the rebuilt Jubilees.

Patriot Jubilee Jubilee rebuilt

5518/5525 5556 5635/5636

Boiler parallel tapered tapered

Superheater 3-row 2-row 3-row

Coal consumption lb/mile 38.4 43.4 37

Coal consumption lb/dbhp 3.41 3.71 3.34

Water consumption Imp gal/mile 30.8 35.4 28

Water cosumption lb/lb coal 8.02 8.14 7.56

[] for class list. Crewe, Derby, and North British Locomotive Company (Queens Park and Hyde Park) shared the production task.

5552-5556 Crewe

5557-5581 NBL, Hyde Park

5582-5606 NBL, Queens Park

5607-5654 Crewe

5655-5664 Derby

5665-5742 Crewe

The last was delivered in November 1936.


Class 5XP Jubilee - rebuilt (Locobase 3760)

The original 5XP design described in Locobase 3071 proved short of steam and Stanier rebuilt two of them in 1942 to improve the breed. The boiler was shortened to 13.25 ft between tube sheets and the grate enlarged to 31 sq ft; Belpaire firebox heating surface increased from 162.4 sq ft to 181 sq ft. Perhaps more important, the number of superheater elements was increased from 14 to 24.

[], accessed 12 August 2007, reproduces a table from Atkins, P. West coast 4-6-0s at work. 1981. Chap. 8 that compares the original Jubilees to the Patriots and the rebuilt Jubilees.

Patriot Jubilee Jubilee rebuilt

5518/5525 5556 5635/5636

Boiler parallel tapered tapered

Superheater 3-row 2-row 3-row

Coal consumption lb/mile 38.4 43.4 37

Coal consumption lb/dbhp 3.41 3.71 3.34

Water cosumption Imp gal/mile 30.8 35.4 28

Water cosumption lb/lb coal 8.02 8.14 7.56

It is this incarnation that OS Nock (RWC V, pl 96) describes when he characterizes them as "hard-working, free-steaming, and very speedy machines. They were just as at home in fast lightly loaded duties, as in slogging up the heavy inclines of the Scottish lines between Glasgow and Carlisle."

[] for class list. Crewe, Derby, and North British Locomotive Company (Queens Park and Hyde Park) shared the production task.

5552-5556 Crewe

5557-5581 NBL, Hyde Park

5582-5606 NBL, Queens Park

5607-5654 Crewe

5655-5664 Derby

5665-5742 Crewe

The last was delivered in November 1936.


Class Black Five - domed (Locobase 1051)

Data from LMS diagram in "Two-Cylinder 4-6-0 Mixed Traffic Tender Engines" , LMS Magazine (October 19340, archived at [], last accessed 20 May 2023; and "5MT 44658 - 45499 4-6-0 LMS Stanier Black Five" on the Preserved British Steam Locomotives website at [], last accessed 22 May 2023; and [] (last accessed 3 October 2006), the site for the group that operates a Black Five survivor. See also Brian Hollingsworth, The Great Book of Trains (London: Salamander Books, Ltd, 1987), pp. 134-135; and "5MT 44658 - 45499 4-6-0 LMS Stanier Black Five" on the Preserved British Steam Locomotives website at [], last accessed 22 May 2023.

Part of an 842-strong locomotive class that has been described as a "go-anywhere, do anything" paragon. The Stanier Black Five is at the head of its class in a comparison of Ten-wheeled locomotives of similar size from around the world. Compared to any standard-gauge locomotive on the main lines when adjusted for loading gauge and axle loading limitatons, its power and reliability are difficult to beat.

Locobase 1050 shows the earlier domeless version, all of which eventually received the domed boilers shown here. The current entry presents the later version with the domed boiler and larger superheater. They retained the Belpaire firebox of the earlier design. The Preserved Locomotives website cited above deserves a look to see how many variants

"The result," says Richard Drew ([]),"...was a highly successful boiler and the Stanier locomotive's high reputation dates from this time." (Hollingsworth also includes "excellent valve events" as permitting the Black Fives to perform so well.)

Hollingsworth sums up the more general opinion of this design: "Arguably the best buy ever made by any railway anywhere in respect to engines capable of handling express passenger trains." They were, he continues, "the most numerous but also the most versatile such class ever to run in Britain." He paints a word portrait of two Black Fives working the former Highland Railway line north of Perth "driven wide open" as it scaled the 20 mile [32.2 km] ascent mostly at 1 in 60 (1.66 percent) from Inverness to the 1,300 ft (396 m) summit at Slochd: "Steaming was usually rock-steady, the sound magnificent, and the firemen's task proportionately onerous as the tonnage moved over this and other neighbouring [sic] inclines."

(Wikipedia pointed out that the 1936 order for 227 locomotives from Armstrong-Whitworth was the largest single purchase by a British railway from a private builder. AW would produce 100 more as would Vulcan Foundry.) Slighly more than half (56%) of all Black Fives were built in 1934-1938 before Great Britain declared war on Germany on 3 September 1939. Five years later production resumed on this domed boiler variant.

Post-war Black Fives contained a number of differences. The last 110 had a coupled wheelbase that measured 3 inches (76.2 mm) longer (15 ft 3 inches/4.65 m) and the engine wheelbase measuring 4 inches (102 mm) more (27 ft 6 inches/8.38 m). 20 were built with Caprotti valve gear. The only design tweak that "took", according to Hollingsworth, "was the installation of of renewable high-manganese steel liners to the axlebox guides. This was successful in increasing considerably the mileage between overhauls."

Many sources note that the free exchange of parts among Black Fives, including ten varieties of boilers, resulted in almost 842 unique engines. Despite four different numbers of flues in the fireboxes, straight or sloped throatplates, domes or domeless, single or double chimnes---all of which were readily recognizable as Black Fives. Although all were delivered with Walschaert outside radial constant-lead valve gear, some postwar engines were fitted with Caprotti and one after an overhaul appeared with outside Stephenson link motion.

Black Fives based at Preston were the last steam locomotives to haul passenger trains on a timetable run and the highest speed recorded for one of the class--96 mph/155 kp--was noted in January 1967.


Class Black Five - domeless (Locobase 1050)

See "5: 1934-1948", Stanier locomotive designs & those of Fairburn & Ivatt, on steamindex website [], last accessed 21 February 2021 and "No 62--Mixed Traffic Engine and Tender (Fitted with Superheater)", Vulcan Iron Works-Established 1830, Newton-Le-Willows, Lancashire (published ca 1935)

Updated 2019-01-19 on Steamindex's

Part of 855-strong locomotive class designed by William Stanier.

This was the earlier version with the domeless boiler, Belpaire firebox, and small superheater. This edition was widely regarded as something of a dog, being steam-strangled in its internal passages and thus easily winded on the grades. See Locobase 1051 for the domed version.


Class Patriot/"Baby Scot"/6P (Locobase 1485)

Data from [], an organization established to raise money to build a new Patriot to be named "Unknown Warrior", last accessed 17 October 2011. Work continued with a new boiler being ordered from Heritage Boiler Steam Services (HBSS) in November 2017..

In G. Freeman Allen's commentary to Great Railway Photographs of Eric Treacy (1987), he notes that the Patriots were the result of mating the earlier Claughton class boiler and Belpaire firebox with the three-cylinder power assemblies of the Royal Scot in 1930. The result, often called "Baby Scots", were nominally ten new engines delivered in 1934 and 42 "rebuilds." Of the last 40 made-over engines, however, "it is highly doubtful that any Claughton metal went into them at all, unless it had been melted down and reforged." This seems certain given the very different specifications the two classes show.

[], accessed 12 August 2007, reproduces a table from Atkins, P. West coast 4-6-0s at work. 1981. Chap. 8 that compares the Patriots to the later Jubilee:

Patriot Jubilee Jubilee rebuilt

5518/5525 5556 5645/5646

Boiler parallel tapered tapered

Superheater 3-row 2-row 3-row

Coal consumption lb/mile 38.4 43.4 37

Coal consumption lb/dbhp 3.41 3.71 3.34

Water consumption Imp gal/mile 30.8 35.4 28

Water consumption lb/lb coal 8.02 8.14 7.56

"Fiery little Lawrie Earl," a well-known engine driver of the time, liked the Baby Scots. Freeman quotes him as pronouncing them "Grand engines, very light on coal." Earl even thought them to have a "better turn of speed than the Royal Scots."

On the other hand, AJ Powell (Powell, A.J. Living with London Midland locomotives. 1977.) is quoted on [] (2 Sept 2004) as offering a much harsher judgement: "Now in principle, there was nothing wrong with such a design. The 'Royal Scot' cylinders and motion, while not quite up to the most enlightened modern standards, proved satisfactory over many years of hard-driven service, and superficially the boiler and firebox were of good size for the job. Yet somehow they just did not click together as they should have done, and the result was an engine that you had to handle understandingly and humour along: hammer it you could not. There were two reasons for this. Firstly the boiler tube proportions were wrong, and secondly the draughting was deficient"

In addition, Powell noted, as the locomotives wore down, they became much more temperamental as gear worked loose.

The Unknown Warrior project's work continued with a new boiler being ordered from Heritage Boiler Steam Services (HBSS) in November 2017..


Class Rebuilt Scot/7P (Locobase 2512)

Data from LMS Drawing Office (Derby) diagram reproduced in an E-book compiled by David Clarke,LMS/BR Class 7 4-6-0 Rebuilds: The Rebuilt Jubilee, Patriot and Royal Scot (Ramsbury, Marlborough, Wiltshire: Crowood Press Ltd, 2014). See also Edward Cecil Poultney, British Express Locomotive Development (London: George Allen and Unwin, 1952), p. 146.

Given some of the early problems of the Royal Scots, the hard use to which the class was put, and William Stanier's developments in boilers and internal streamlining, a class of so handy a size as the Royal Scot was a good candidate for a rebuild. And so they were beginning in 1942. Hollingsworth (1982) contends that in many cases only the cabs, tenders, and nameplates remained of the old engine. The centerpiece of these razeed engines was a new tapered, domeless boiler still shorter between the tube sheets than earlier designs and fitted with 28 superheater elements. (Bryan Attewell ([] Steam locomotive simulator (April 2000 edition) gives slightly different heating surface data -- 1,862 sq ft evaporative, 348 sq ft superheating.)

The program, Hollingsworth says, "was a great success. The new engines stood up to all the abuse of high speed running, heavy loads, and wartime neglect better than the originals and then after the war covered themselves in glory."

On the other hand, Steamindex quotes A J Powell extensively on two big issues with the Rebuilt Scots. One was the ride quality, which ranged from rough to atrocious. Powell spent two months with the class and after "...weeks of riding on 'Scots' up and down the West Coast mainlines, until his ribs bore the impression of every cabside beading", he recommended three changes:

-- Stiffen the coupled springs to minimize the locomotive's tendency to roll,

-- Eliminate the practice of using gunmetal liners in the axlebox because of their tendency to fall off and increase lateral play to an unwanted degree, and

-- Soften the bogie check springs and use friction damping on the bogie slides. The effect of this last adjustment was to lessen the tendency of the bogie to recenter the locomotive too sharply. These modifications and the discovery of significant errors in counter-balancing due to changes in coupling-rod design smoothed the ride.

Smoke deflector design actually contributed to the masking of the driver's view. Only those fitted with the standard British Railways smoke deflector demonstrated any effectiveness.

Retirements began in 1962 and ended in 1966.


Class Royal Scot - 7P (Locobase 2511)

Data from Edward Cecil Poultney, British Express Locomotive Development (London: George Allen and Unwin, 1952), p. 146. See also "4 6-0 Express Passenger Engines, 'Royal Scot' Class", LMS Magazine (June 1928).

Henry Fowler designed these three-cylinder engines built by North British. 50 were delivered in 1927, 20 more in 1930. They had a relatively short, straight barrel with small steam dome, Belpaire firebox, and three sets of Walschaerts gear. Hollingsworth (1982) notes that a substantial rebuilding essentially divided this class into two designs -- one before and one after. One early problem was piston valves that when worn leaked so badly that steam consumption increased by 50% (!) and the vapor obscured the view.

See "Rebuilt Scot" (Locobase 2512) for further information.

Principal Dimensions by Steve Llanso of Sweat House Media

Class5XP Jubilee5XP Jubilee - rebuiltBlack Five - domedBlack Five - domelessPatriot/"Baby Scot"/6P
Locobase ID3071 3760 1051 1050 1485
RailroadLMSLMSLMSLMSLMS
CountryGreat BritainGreat BritainGreat BritainGreat BritainGreat Britain
Whyte4-6-04-6-04-6-04-6-04-6-0
Number in Class19127427052
Road Numbers5552-57425635-56365000-5499, 4758-49995000-5069
GaugeStdStdStdStdStd
Number Built1917427052
BuilderLMSLMSLMSLMSLMS
Year19341942193619341935
Valve GearWalschaertWalschaertWalschaertWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m)15.33 / 4.6715.83 / 4.8215 / 4.5715 / 4.5715.33 / 4.67
Engine Wheelbase (ft / m)27.59 / 8.4127.59 / 8.4127.17 / 8.2827.17 / 8.2827.46 / 8.37
Ratio of driving wheelbase to overall engine wheelbase 0.56 0.57 0.55 0.55 0.56
Overall Wheelbase (engine & tender) (ft / m)53.23 / 16.2263.65 / 19.4052.29 / 15.94
Axle Loading (Maximum Weight per Axle) (lbs / kg)40,096 / 18,18744,912 / 20,372
Weight on Drivers (lbs / kg)134,400 / 60,963137,200 / 62,233117,135 / 53,206118,720 / 53,851133,840 / 60,709
Engine Weight (lbs / kg)180,880 / 82,046183,560 / 83,262161,504 / 73,257156,856 / 71,149180,880 / 82,046
Tender Loaded Weight (lbs / kg)121,184 / 54,968120,176 / 54,511121,016 / 54,89294,976 / 43,080
Total Engine and Tender Weight (lbs / kg)302,064 / 137,014281,680 / 127,768277,872 / 126,041275,856 / 125,126
Tender Water Capacity (gals / ML)4800 / 18.184000 / 15.154800 / 18.184800 / 18.18
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) 9.90 / 910.10 / 9.2010.10 / 9 9.90 / 9
Minimum weight of rail (calculated) (lb/yd / kg/m)75 / 37.5076 / 3865 / 32.5066 / 3374 / 37
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)81 / 205781 / 205772 / 182972 / 182981 / 2057
Boiler Pressure (psi / kPa)225 / 15.50250 / 17.20225 / 15.50225 / 15.50200 / 13.80
High Pressure Cylinders (dia x stroke) (in / mm)17" x 26" / 432x660 (3)17" x 26" / 432x660 (3)18.5" x 28" / 470x71118.5" x 28" / 470x71118" x 26" / 457x660 (3)
Tractive Effort (lbs / kg)26,612 / 12071.0129,569 / 13412.2925,455 / 11546.2125,455 / 11546.2126,520 / 12029.28
Factor of Adhesion (Weight on Drivers/Tractive Effort) 5.05 4.64 4.60 4.66 5.05
Heating Ability
Tubes (number - dia) (in / mm)160 - 2" / 51159 - 1.875" / 48160 - 2" / 51
Flues (number - dia) (in / mm)14 - 5.25" / 13324 - 5.125" / 13014 - 5.25" / 133
Flue/Tube length (ft / m)14.25 / 4.3414.25 / 4.3413.25 / 4.0414.25 / 4.3414.25 / 4.34
Firebox Area (sq ft / m2)162.40 / 15.09195 / 18.12171 / 15.89156 / 14.49183
Grate Area (sq ft / m2)29.50 / 2.7431.20 / 2.9028.65 / 2.6627.80 / 2.5830.50 / 2.83
Evaporative Heating Surface (sq ft / m2)1625 / 150.971862 / 172.991479 / 137.401616 / 150.131735 / 161.19
Superheating Surface (sq ft / m2)228 / 21.18357 / 33.17359 / 33.35228 / 21.18365 / 33.91
Combined Heating Surface (sq ft / m2)1853 / 172.152219 / 206.161838 / 170.751844 / 171.312100 / 195.10
Evaporative Heating Surface/Cylinder Volume158.60181.74169.78185.51151.05
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation66387800644662556100
Same as above plus superheater percentage74349048773670067137
Same as above but substitute firebox area for grate area40,92556,55046,17039,31242,822
Power L113,30819,92917,24813,78613,951
Power MT654.89960.70973.88768.01689.40

Principal Dimensions by Steve Llanso of Sweat House Media

ClassRebuilt Scot/7PRoyal Scot - 7P
Locobase ID2512 2511
RailroadLMSLMS
CountryGreat BritainGreat Britain
Whyte4-6-04-6-0
Number in Class270
Road Numbers61006100
GaugeStdStd
Number Built270
BuilderLMSNorth British
Year19421927
Valve GearWalschaertWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m)15.33 / 4.6715.33 / 4.67
Engine Wheelbase (ft / m)27.50 / 8.3827.50 / 8.38
Ratio of driving wheelbase to overall engine wheelbase 0.56 0.56
Overall Wheelbase (engine & tender) (ft / m)64.92 / 19.7952.02 / 15.86
Axle Loading (Maximum Weight per Axle) (lbs / kg)45,808 / 20,86546,000 / 20,865
Weight on Drivers (lbs / kg)136,640 / 61,979140,017 / 63,511
Engine Weight (lbs / kg)185,920 / 84,332190,203 / 86,275
Tender Loaded Weight (lbs / kg)122,416 / 55,52799,456 / 45,113
Total Engine and Tender Weight (lbs / kg)308,336 / 139,859289,659 / 131,388
Tender Water Capacity (gals / ML)4800 / 18.184200 / 15.91
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) 9.90 / 9 6.10 / 5.50
Minimum weight of rail (calculated) (lb/yd / kg/m)76 / 3878 / 39
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)81 / 205781 / 2057
Boiler Pressure (psi / kPa)250 / 17.20260 / 17.90
High Pressure Cylinders (dia x stroke) (in / mm)18" x 26" / 457x660 (3)18" x 26" / 457x660 (3)
Tractive Effort (lbs / kg)33,150 / 15036.6034,476 / 15638.07
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.12 4.06
Heating Ability
Tubes (number - dia) (in / mm)198 - 1.75" / 44180 - 2" / 51
Flues (number - dia) (in / mm)28 - 5.125" / 13027 - 5.125" / 130
Flue/Tube length (ft / m)13 / 3.9614.50 / 4.42
Firebox Area (sq ft / m2)195 / 18.12189 / 17.56
Grate Area (sq ft / m2)31.20 / 2.9031.20 / 2.90
Evaporative Heating Surface (sq ft / m2)1862 / 172.032080 / 193.24
Superheating Surface (sq ft / m2)348 / 34.11399 / 37.07
Combined Heating Surface (sq ft / m2)2210 / 206.142479 / 230.31
Evaporative Heating Surface/Cylinder Volume162.10181.08
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation78008112
Same as above plus superheater percentage90489410
Same as above but substitute firebox area for grate area56,55057,002
Power L117,53820,217
Power MT848.90954.97

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