County Donegal 4-6-4 Locomotives in Ireland

Class Details by Steve Llanso of Sweat House Media

Class Class 4 (Locobase 2702)

Data from R M Livesey, "Rolling-Stock on the Principal Irish Narrow-Gauge Railways", Engineering, Volume 94, (2 August 1912), pp. 169-176, table on p. 175.

Hudson (aka Baltic) tanks of a rated power between the two classes of Adriatic tanks on the same railway (Locobase 2700-2701).

SJ Carse, writing in the Railway Preservation Society of Ireland (RPSI)'s excellent journal Five Foot Three (appearing on [], visited in November 2002), offers a low opinion of the type in its original form. They steamed poorly even as they gobbled coal. Indeed their appetite ranged as high as 45 lb/mile while the Class 5s consumed but 29. (Carse notes parenthetically that the builder Nasmyth Wilson had not wanted to use 15" cylinders.)

The problem may have been related to a boiler overstuffed with firetubes. When #12 came in for an overhaul, Donegal's Livesy removed the top row of tubes, which materially improved steaming qualities.

All were superheated in the 1920s and this proved to be a key improvement. Their newfound power was applied on all kinds of service.

Names, works numbers, and scrapping dates were: Eske (697, 1954), Owenea (698, 1952), Erne (699, 1968), and Mourne (700, 1952).

Principal Dimensions by Steve Llanso of Sweat House Media

ClassClass 4
Locobase ID2702
RailroadCounty Donegal
Number in Class4
Road Numbers12-15
Number Built4
BuilderNasmyth Wilson
Valve Gear
Locomotive Length and Weight
Driver Wheelbase (ft / m)9 / 2.74
Engine Wheelbase (ft / m)25.17 / 7.67
Ratio of driving wheelbase to overall engine wheelbase 0.36
Overall Wheelbase (engine & tender) (ft / m)25.17 / 7.67
Axle Loading (Maximum Weight per Axle) (lbs / kg)19,712 / 8941
Weight on Drivers (lbs / kg)58,240 / 26,417
Engine Weight (lbs / kg)99,680 / 45,214
Tender Loaded Weight (lbs / kg)
Total Engine and Tender Weight (lbs / kg)99,680 / 45,214
Tender Water Capacity (gals / ML)1800 / 6.82
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) 2.70 / 3
Minimum weight of rail (calculated) (lb/yd / kg/m)32 / 16
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)45 / 1143
Boiler Pressure (psi / kPa)160 / 11
High Pressure Cylinders (dia x stroke) (in / mm)15" x 21" / 381x533
Tractive Effort (lbs / kg)14,280 / 6477.31
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.08
Heating Ability
Tubes (number - dia) (in / mm)
Flues (number - dia) (in / mm)
Flue/Tube length (ft / m)
Firebox Area (sq ft / m2)80 / 7.43
Grate Area (sq ft / m2)12 / 1.11
Evaporative Heating Surface (sq ft / m2)723 / 67.17
Superheating Surface (sq ft / m2)
Combined Heating Surface (sq ft / m2)723 / 67.17
Evaporative Heating Surface/Cylinder Volume168.33
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation1920
Same as above plus superheater percentage1920
Same as above but substitute firebox area for grate area12,800
Power L13137
Power MT356.24

All material Copyright ©
Wes Barris