Data from "New 'Baltic' Tank Locomotives Glagow & South Western", Locomotive Magazine, Volume XXVIII [28], No 358 (15 June 1922), p, 178; and "New Passenger Tank Locomotives, Glasgow and South Western Railway, LM, No 359, pp. 194-198; color illustration p. 399.. See also Ahrons (1927), "4-6-4 Main Lime Tank Engines, Glasgow & South Western Railway," The Railway Magazine, Volume 51 (July 1922), p. 49; and "New Express Tank Locomotives, Glasgow & South Western Railway", Railway Engineer, Volume 43, No 8 (August 1922), pp. 298-301.
RH Whitelegg Hudson tank. Whitelegg, the G&SW's Chief Mechanical Engineer, was credited in the Railway Magazine report as having introduced the heavy express tank locomotive to British railway service. This sextet's duty was to haul the "heavy fast and ever-growing traffic of the various coast routs serving the numerous popular holiday resorts of the Ayrshire coast and in connection with the Clyde steamer services, both by railway-owned and by private vessels."
They also hooked up to Anglo-Scottish trains on a "very steeply graded" section between Glasgow and Kilmarnock. See the Railway Engineer report for a very detailed discussion of the G&SW's operating area.
Ten-inch (254 mm) patent Allen & Simmonds piston valves supplied steam to the cylinders. Both bogies enjoyed a total play of 5 1/2" (140 mm).
A couple of sidelights from the RE account are the provision of Skefco ball bearings to the return crank on the driver and a characterization of the cab design as "roomy, well ventilated and affording a very clear lookout in both directions."
| Principal Dimensions by Steve Llanso of Middle Run Media | |
|---|---|
| Class | Class 540 |
| Locobase ID | 2360 |
| Railroad | Glasgow & South Western |
| Country | Great Britain |
| Whyte | 4-6-4T |
| Number in Class | 6 |
| Road Numbers | 540-545 |
| Gauge | Std |
| Number Built | 6 |
| Builder | North British |
| Year | 1922 |
| Valve Gear | Walschaert |
| Locomotive Length and Weight | |
| Driver Wheelbase (ft / m) | 13.17 / 4.01 |
| Engine Wheelbase (ft / m) | 39 / 11.89 |
| Ratio of driving wheelbase to overall engine wheelbase | 0.34 |
| Overall Wheelbase (engine & tender) (ft / m) | 39 / 11.89 |
| Axle Loading (Maximum Weight per Axle) (lbs / kg) | 40,320 / 18,289 |
| Weight on Drivers (lbs / kg) | 120,960 / 54,867 |
| Engine Weight (lbs / kg) | 221,920 / 100,661 |
| Tender Loaded Weight (lbs / kg) | 70,560 |
| Total Engine and Tender Weight (lbs / kg) | 292,480 |
| Tender Water Capacity (gals / ML) | 2880 / 10.91 |
| Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) | 3.85 / 4 |
| Minimum weight of rail (calculated) (lb/yd / kg/m) | 67 / 33.50 |
| Geometry Relating to Tractive Effort | |
| Driver Diameter (in / mm) | 72 / 1829 |
| Boiler Pressure (psi / kPa) | 180 / 1240 |
| High Pressure Cylinders (dia x stroke) (in / mm) | 22" x 26" / 559x660 |
| Tractive Effort (lbs / kg) | 26,741 / 12129.53 |
| Factor of Adhesion (Weight on Drivers/Tractive Effort) | 4.52 |
| Heating Ability | |
| Tubes (number - dia) (in / mm) | 141 - 2" / 51 |
| Flues (number - dia) (in / mm) | 21 - 5.25" / 133 |
| Flue/Tube length (ft / m) | 15.33 / 4.67 |
| Firebox Area (sq ft / m2) | 156 / 14.49 |
| Grate Area (sq ft / m2) | 30 / 2.79 |
| Evaporative Heating Surface (sq ft / m2) | 1730 / 160.72 |
| Superheating Surface (sq ft / m2) | 255 / 23.69 |
| Combined Heating Surface (sq ft / m2) | 1985 / 184.41 |
| Evaporative Heating Surface/Cylinder Volume | 151.23 |
| Computations Relating to Power Output (More Information) | |
| Robert LeMassena's Power Computation | 5400 |
| Same as above plus superheater percentage | 6102 |
| Same as above but substitute firebox area for grate area | 31,730 |
| Power L1 | 9073 |
| Power MT | 496.09 |