County Donegal 2-6-4 Locomotives in Ireland


Class Details by Steve Llanso of Sweat House Media

Class Class 5/Class Donegal (Locobase 2700)

Data from "New Tank Locomotives, County Donegal Joint Committee", The Locomotive Magazine, Vol XV (15 January 1909), p. 9. See also R M Livesey, "Rolling-Stock on the Principal Irish Narrow-Gauge Railways", Proceedings of the Institute of Mechanical Engineers (London: IME, 1912), pp. 606-608; reproduced in Engineering, Volume 94, (2 August 1912), pp. 169-176, table on p. 175. Works numbers were 828-832 in 1907

Adriatic tanks of moderate size. The boiler design, which had first been installed in the Class 3 4-4-4s (Locobase 2689) had an unusual pattern of tubes in which the 132 tubes were divided into groups of 61 with a vertical space between the groups "...so as to allow of the steam being liberated more readily." The separate bundles were placed in vertical rows ( o o o rather than the more usual alternating spacing (o o o

o o o) o o ).

In his 1912 report, Livesey pointed to the boiler pressure increase, a 1" (25.4 mm) increase in cylinder stroke, moree adhesive weight thanks to the addditon of the third driven axle, and a single axle radial axle in front as reasons for a result that "came up to all expectations." Compared to the Class 4s, the Class 5s had "proved itself eminently capable of doing the same work .... at rather better speeds, and at greatly reduced expense." Coal consumption dropped by 10 lb/mile (2.8 kg/km) in the first year and had averaged 6 lb/mile (1.69 kg/km) less up to 1912.

LM reported "These engines are economical in coal consumption, and capable of hauling 120 tons up a gradient of 1 in 50 (2%) at a speed of 20 mph."

Originally named Donegal, Glenties, Killybegs, Letterkenny, and Raphoe. Except for Letterkenny, scrapped in 1940, they were renamed Meenglas, Drumboe, Columbkille, and Foyle. All but the last were preserved.

See Locobase 2701 for the superheated trio produced in 1912


Class Class 5A (Locobase 2701)

Data from RWA Salter in Railway Magazine in Feb 1931 (see cdrrs.future.easyspace.com/510d.html/ ; "County Donegal Joint Committee", Locomotive Magazine, Volume XXVIII [18] (15 May 1912), p. 92. See also R M Livesey, "Rolling-Stock on the Principal Irish Narrow-Gauge Railways", Proceedings of the Institute of Mechanical Engineers (London: IME, 1912), pp. 606-608; reproduced in Engineering, Volume 114, (2 August 1912), pp. 169-176, table on p. 175; and S J Carse, "Steam on the County Donegal", Five Foot Three, No 11 (Summer 1971), accessed at [link][link], originally November 2002, last 22 December 2023. Works numbers were 958, 956-957 in 1912.

R M Livesey, the County Donegal's locomotive superintendent, opened his report on "Rolling Stock ..." by contending that the only advantage to building a narrow-gauge railway was the cost per mile compared to" fully equipped" standard-gauge railways. And since the British Board of Trade required narrow-gauge lines to be fully equipped, no savings were in fact realized.

"No railway should be built of narrow gauge", said Livesey, "if the cost will exceed 5,000 pounds per mile, and then only if the proposed line will be for ever [sic] isolated from those of standard gauge and if the traffic is always likely to be small." It would be better, he added, to build a light railway on the standard gauge.

Livesey then turned his attention to the difficulties of designing and firing narrow-gauge fireboxes. His detailed description of all the adverse consequences is worth looking up on p. 170 as is an earlier discussion on firebox problems in the 23 February 1912 Engineering, pp. 187-188

In the same year, Livesey took delivery of larger Adriatic tanks than the 1907 quintet shown in Locobase 2700 and fitted with superheaters, inside-admission 7" (178 mm) piston valves. Salter reported that this class could haul a 230-ton passenger train at an average speed of 35 mph (56.4 km/h) over the 46 miles (74 km) between Derry and Donegal without requiring refueling and water. LM reported that the engines possessed "an apparently unlimited reserve of steam" as shown by their ability to steam up long 2% grades pulling 200 tons at more than 20 mph (32 km/h). "[N]othing is wanted that would tend to economy, or facilitate working and they do the greatest possible credit to their owners and buiders.

SJ Carse, writing in the RPSI's Five Foot Three (appearing on [link], visited in November 2002, claimed the Class 5s were "in every way a good engine."

Their works numbers were #2A Stranorlar (956), later #2 Blanche; #3A Strabane (957), later #3 Lydia; and #21 Ballyshannon (958), later #1 Alice.

Principal Dimensions by Steve Llanso of Middle Run Media
ClassClass 5/Class DonegalClass 5A
Locobase ID2700 2701
RailroadCounty DonegalCounty Donegal
CountryIrelandIreland
Whyte2-6-4T2-6-4T
Number in Class53
Road Numbers16-2021, 2A, 3A
Gauge3'3'
Number Built53
BuilderNasmyth WilsonNasmyth Wilson
Year19071912
Valve GearWalschaertWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m)10 / 3.0510 / 3.05
Engine Wheelbase (ft / m)26.25 / 827.25 / 8.31
Ratio of driving wheelbase to overall engine wheelbase 0.38 0.37
Overall Wheelbase (engine & tender) (ft / m)26.25 / 827.25 / 8.31
Axle Loading (Maximum Weight per Axle) (lbs / kg)20,160 / 914423,072 / 10,465
Weight on Drivers (lbs / kg)59,920 / 27,17968,566 / 31,101
Engine Weight (lbs / kg)95,200 / 43,182112,896 / 51,209
Tender Loaded Weight (lbs / kg)
Total Engine and Tender Weight (lbs / kg)95,200 / 43,182112,896 / 51,209
Tender Water Capacity (gals / ML)1200 / 4.551800 / 6.82
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) 2.80 / 3 2.80 / 2.50
Minimum weight of rail (calculated) (lb/yd / kg/m)33 / 16.5038 / 19
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)48 / 121948 / 1219
Boiler Pressure (psi / kPa)175 / 1210175 / 1210
High Pressure Cylinders (dia x stroke) (in / mm)14" x 21" / 356x53315.5" x 21" / 394x533
Tractive Effort (lbs / kg)12,755 / 5785.5815,635 / 7091.93
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.70 4.39
Heating Ability
Tubes (number - dia) (in / mm)132 - 1.75" / 4482 - 1.75" / 44
Flues (number - dia) (in / mm)10 - 5.25" / 133
Flue/Tube length (ft / m)10.50 / 3.2011 / 3.35
Firebox Area (sq ft / m2)76 / 7.0678 / 7.25
Grate Area (sq ft / m2)11.50 / 1.0711.50 / 1.07
Evaporative Heating Surface (sq ft / m2)713 / 66.24642 / 59.64
Superheating Surface (sq ft / m2)106 / 9.85
Combined Heating Surface (sq ft / m2)713 / 66.24748 / 69.49
Evaporative Heating Surface/Cylinder Volume190.56139.98
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation20132013
Same as above plus superheater percentage20132294
Same as above but substitute firebox area for grate area13,30015,561
Power L140906062
Power MT451.45584.74

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