War Department Light Railways 4-6-0 Locomotives in Great_Britain


Class Details by Steve Llanso of Sweat House Media

Class 10-12-D (Locobase 4985)

Data from Lt Col B W Guppy, "A Technical Description of British Light Railways in France", Professional Memoirs, Corps of Engineers, United States Army and Engineer Department At Large, Vol. XI, No 55 (January-February 1919), p. 190. See also Locobase's number comes from WJK Davies Light Railways of the First World War (New York: Reprints of Economic Classics, 1968) and The military railways website homepages.tesco.net/~martyn.witt/milrly/mil_rly_hist_c_4.htm and DeGolyer, Vol 57, pp. 164-170.

Witt notes that when the British military realized they needed a large number of locomotives for their forward-area narrow-gauge railway system in France, they found that British manufacturers couldn't meet the demand. So Baldwin, in the then-neutral United States received a contract for 450.

The engines were built in several batches. Works numbers were:

1915

February 41897-41902; September 44178-44182

1916

October 44335-44339, 44351-44390; November 44489-44494;

December 44507-44556, 44635-44659, 44681-44688

1917

January 44695-44794, 44938-45037; February 45133-45236; March 45374-45383; April 45398-45433

1918

January 47529-47537

Baldwin's productivity was such, the website notes, that they "produced 450 ...in the same time taken by the UK's Hunslet Engine Company to produce just 45." [In fairness to Hunslet, it's likely that the British company had other military subcontracts to fulfill.].

WJK Davies, in his Light Railways of the First World War (New York: Reprints of Economic Classics, 1968) says that only 9 of the 495 ordered failed to enter service within a year of the first order (they were lost at sea) "a truly fantastic building achievement by any standard." Although intended for a short life, these locomotives used copper fireboxes and brass tubes at the insistence of the War Office. "Nevertheless," says Davies, "the locomotives were efficient and workmanlike machines capable of taking hard punishment and designed for easy maintenance."

[link], the Welsh Highlands Railway site, adds that one block of works numbers ran from 45133-45236. This was one of the later batches. DLR numbers originally covered 1001-1104; later however 1005 to 1150 were renumbered 546-700. (It's the odd logic often displayed in such actions that engines with higher numbers then actually represented earlier Baldwin products.) Another chapter in this website's history of military railroads notes that 25 of these Ten-wheeler tanks went to Palestine in 1917-1918.

Colonel Guppy criticized two features common to both the Baldwin and Hunslet tanks: the absence of a rocking grate, which added time and effort to cleaning the ashpan, and the use of ferrules in the ends of boiler tubes. Guppy concedes " a little reduction in flue leakage", but sternly adds, "...the detriment to the locomotive by the ferreling [sic[ of the tubes more than offset the advantage ...Ferreling the flues means increasing the diameter of the flue opening, allowing a smaller space for the passage of fire box gases, and also offers a greater opportunity for the blocking of flues."

Six of this class wound up on the Ashover Light Railway. See Locobase 4984 and website

users.breathemail.net/djracecars/ashover/locomotives.htm --

Gareth Roberts of the Ashover site comments on a bad quality of these otherwise sturdy and reliable engines. They had, he notes, "exceptionally wide side tanks ...If [the engines] were stood on canted track for any length of time (i.e., one rail higher than the other, common practice on curves) water would run from one tank to the other via the balancing pipe and the weight of the heavier tank could tip the engine off the track, something which occurred several times during construction of the lines."

WHR's 590, purchased in 1923 for 240 pounds from the Government Property Disposals Board, gained a reputation as a rough rider and was relegated to freight service. It was scrapped in 1942.


Class Hunslet (Locobase 5393)

Locobase's number comes from WJK Davies Light Railways of the First World War (New York: Reprints of Economic Classics, 1968). See also Lt Col B W Guppy, "A Technical Description of British Light Railways in France", Professional Memoirs, Corps of Engineers, United States Army and Engineer Department At Large, Vol. XI, No 55 (January-February 1919), p. 190; and Steve Green, "The Hunslet 'War Office' class 4-6-0Ts," The Corkscrew, Newsletter of the Wimborne Railway Society, Issue 54 (December 2009), pp. 10-16; and "Narrow Gauge Military Railway Locomotives on the Western Front", Locomotive, Volume XXVI [26] (15 June 1920), pp. 130-132.

Known by their builder as the War Office tanks, these were the smallest of the WLDR "main-line" designs, although their proportions seem quite lusty in a pocket-rocket way. Steve Green's article in the Corkscrew says they were based on Hunslet's one-off 0-6-0T "Hans Sauer"built in 1906 and later converted to a tender engine of sorts.

The first order for 45 came in March 1916 with a follow-up of 30 in August. 80 more were ordered in January 1918 and later, but only 16 made it to Italy and 2 to Egypt. The others were delivered to the WD and then disposed of.

The Industrial Locomotives website -- [link] -- displayed the following production record(23 May 2004):

1916 : 1213 - 1250 (WDLR 301 - 338)

1917 : 1251 - 1287 (WDLR 339 - 375)

1918 : 1295 - 1328 (WDLR 2323 - 2356)

1919 : 1329 - 1334 (WDLR 2357 - 2362)

1919 : 1336 - 1355 (WDI.R 3220 - 3239)

And 19 for the 2' 6" gauge:

1919 : 1356 - 1375 (WDLR 3240 - 3259)

Davies summarizes their value thusly: "[They were] the most popular locomotives with train crews and were highly prized by any operating company to which they were allocated. They were strongly built, powerful, reliable, and comparatively stable. Their worth is reflected in the fact that all but 18 are definitely known to have survived the war and found willing buyers."

Green says they were rated at 286 tons on the level and 80 tons up a 1:50 (2%) grade.

But Colonel Guppy criticized two features common to both the Baldwin and Hunslet tanks: the absence of a rocking grate, which added time and effort to cleaning the ashpan, and the use of ferrules in the ends of boiler tubes. Guppy concedes the latter fittings did result in "...a little reduction in flue leakage", but sternly adds, "...the detriment to the locomotive by the ferreling [sic[ of the tubes more than offset the advantage ...Ferreling the flues means increasing the diameter of the flue opening, allowing a smaller space for the passage of fire box gases, and also offers a greater opportunity for the blocking of flues."

Some were modified with "tenders" (water tanks on a flat car) to reduce axle-load. Davies says that many received this treatment when used in the Argentine by potato-carrying railways.

See [link] (confirmed 12 August 2005) for a serial-by-serial listing of the final disposition. Hughes's comments on the design are also worth noting, beginning with the rhetorical question:

"What is significant about these locos?

"Apart from being one of the largest class of one single type of narrow gauge loco built within the UK the vast majority were also completed within the space of three years."

To set the context for what an accomplishment that was, Hughes adds that Hunslet was then also manufacturing "...howitzers, shells, and machinery to make shells as well as a limited number of other locos" He seals his observation on the unrivalled pace of construction by adding: "By comparison, in peace time they averaged about 40 locos per year."

But there's more: "The other remarkable feature of these machines is the diverse locations that they and the nine built post war, ended up in. Scottish Highlands, to the Pampas of Argentina, Harrogate gasworks to Australian Canefields, Oxfordshire Ironstone to Palestinian Power Stations." At least 20 of the Buenos Aires Great Southern stud of 25+ WarOffs were converted to 4-6-0 tender engines because of the poor roadbed, which tended to induce oscillations in the tank engines.

Principal Dimensions by Steve Llanso of Middle Run Media
Class10-12-DHunslet
Locobase ID4985 5393
RailroadWar Department Light RailwaysWar Department Light Railways
CountryGreat BritainGreat Britain
Whyte4-6-0T4-6-0T
Number in Class495150
Road Numbers501-545, 701-1150
Gauge60 cm60 cm
Number Built495150
BuilderBaldwinHunslet Engine Co
Year19151917
Valve GearWalschaertStephenson-Belpaire
Locomotive Length and Weight
Driver Wheelbase (ft / m) 5.83 / 1.78 5.50 / 1.68
Engine Wheelbase (ft / m)12.17 / 3.7113 / 3.96
Ratio of driving wheelbase to overall engine wheelbase 0.48 0.42
Overall Wheelbase (engine & tender) (ft / m)13 / 3.96
Axle Loading (Maximum Weight per Axle) (lbs / kg)69207840 / 3556
Weight on Drivers (lbs / kg)23,251 / 10,54623,521 / 10,669
Engine Weight (lbs / kg)32,480 / 14,73331,471 / 14,275
Tender Loaded Weight (lbs / kg)
Total Engine and Tender Weight (lbs / kg)
Tender Water Capacity (gals / ML)396 / 1.50449 / 1.70
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) 0.90 0.90 / 0.80
Minimum weight of rail (calculated) (lb/yd / kg/m)13 / 6.5013 / 6.50
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)23.50 / 59724 / 610
Boiler Pressure (psi / kPa)180 / 1240160 / 1100
High Pressure Cylinders (dia x stroke) (in / mm)9" x 12" / 229x3059.5" x 12" / 241x305
Tractive Effort (lbs / kg)6328 / 2870.346137 / 2783.70
Factor of Adhesion (Weight on Drivers/Tractive Effort) 3.67 3.83
Heating Ability
Tubes (number - dia) (in / mm)83 - 1.5" / 3886 - 1.75" / 44
Flues (number - dia) (in / mm)
Flue/Tube length (ft / m) 7.06 4.29 / 1.31
Firebox Area (sq ft / m2)23.50 / 2.1837 / 3.44
Grate Area (sq ft / m2) 5.50 / 0.51 3.95 / 0.37
Evaporative Heating Surface (sq ft / m2)255 / 23.70205 / 19.05
Superheating Surface (sq ft / m2)
Combined Heating Surface (sq ft / m2)255 / 23.70205 / 19.05
Evaporative Heating Surface/Cylinder Volume288.60208.23
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation990632
Same as above plus superheater percentage990632
Same as above but substitute firebox area for grate area42305920
Power L129722535
Power MT845.40712.82

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