Data from diagram in Ralph Tutton, "The Steam Rail Motor Cars Built by the Gloucester Railway Carriage and Wagon Company Limited for the Great Western Railway, Gloucestershire Society for Industrial Archaeology Journal for 1993, pp. 29-36, archived at [], last accessed 2 April 2017. See also "Road and Rail Motor Cars as an Auxiliary Passenger Service", Railway Age, Volume XLIII [43], No 14 (5 April 1907), p. 576.
Locobase 10592 shows the first of these Swindon-built steam rail motors and describes the basic layout as well as their intended use by the Great Western. Tutton's detailed account reproduced a GWR diagram from 1907. It shows that among the production batches built, any changes were relatively minor. Swindon built the bulk of the rail motors. ,Kerr Stuart (15-16, 61-72) built just engine units and the Gloucester RC&WC (73-80) produced eight carriages.
The interior divisions in 81-83, front to back, were a 19 ft 7 3/8 (5.98 m) motor compartment, 6 ft 7 1/2 in (2.02 m) luggage compartment, a 8' 6" (2.59 m), 12-seat smoking section, a central vestibule with one (Gloucester) or two (Swindon) door panels, and 28 seats in 9 ft (2.74 m) a side bench seats and four transverse seat groups on each side of an aisle along an additional 11 ft 6 in (3.51 m).
In the same year these rail motors entered service, an American delegation sampled the service and described it favorably. They clocked the speed range as 29-45 mph and quoted the driver as saying the car could reach 50 mph. By then the car had been in "successful operation" for three years and "ran smoothly, without noticeable vibration."
A glimpse of the scale of steam motor car operations on the GWR sees 1913 as the most intense, when the fleet traveled "well over" 2 million miles (322,000,000 km).
Data from H. G Archer, "Railway Motor-Cars", The World's Work, Vol II, No 12 (November 1903), pp. 594-595. See also an extended review of early service in "The New Great Western Motor-Coach Services," Engineer (6 May 1904), pp. 461-462; George E Walsh, "Motor Cars as Trunk Railway Feeders", Cassier's Magazine, Vol 28 (1905), pp. 301-302. "6-coupled Engine for Auto-Train," The Railway Magazine, Vol 22 (January 1908), p. 40; and Ralph Tutton, "The Steam Rail Motor Cars Built by the Gloucester Railway Carriage and Wagon Company Limited for the Great Western Railway, Gloucestershire Society for Industrial Archaeology Journal for 1993, pp. 29-36, archived at [], last accessed 2 April 2017.
The Stroud Valley was seen by G J Churchward as prime territory to test the idea of a steam rail motor car as a counter to electric railway service. Seven miles of thickly settled towns between Chalford and Stonehouse offered the prospect of a steady patronage. Walsh pointed out that in addition to countering the electric railway, the company hoped to encourage "...the development of promising sections of the country." This would be accomplished by GWR-owned motor cars, some of which had already entered service as early as 1904.
Compared to other steam rail motor prime movers, Churchward's design used a larger boiler pressed to a higher degree to supply steam to a greater cylinder volume. Coach capacity included 16 seats set up transversely and 36 seats in longitudinal benches. The cars could be operated from either end.
A further exploration of the concept led to the adoption of the two-coach auto-train in which the locomotive was coupled to both coaches. This was outlined in the Railway Magazine article of January 1908. Typically, the engine was an 0-6-0T shunting "Wolverhampton tank" that was shrouded by coach work to give the auto-train a consistent look. For some runs, the GWR would couple two of these together and create a coach-locomotive-coach-coach-locomotive-coach combination measuring 320 feet in length. The engine had 952 sq ft of heating surface in a boiler pressed to 165 psi, 16 1/2" x 24" cylinders, 49 1/2" drivers; it weighed 42 tons 17 cwt (95,984 lb).
By 1908, 112 power units and 99 carriage units had been completed.
Data from Charles S Lake, "Railway Motor Cars in Great Britain", The Engineering Review, Volume 13, No 7 (July 1905), p. 56, 61-62. See also Ralph Tutton, "The Steam Rail Motor Cars Built by the Gloucester Railway Carriage and Wagon Company Limited for the Great Western Railway, Gloucestershire Society for Industrial Archaeology Journal for 1993, pp. 29-36, archived at [], last accessed 2 April 2017.
Locobase 10592 shows the first of these Swindon-built steam rail motors. The #2 was slightly smaller and had its boiler set at a lower pressure. According to Lake, the design was sufficiently powerful to "haul a number of trailing vehicles, such as horse boxes, goods trucks, &c."
Behind the locomotive section, which also consisted of the front, powered bogie, the arrangement included 16 smoking seats arranged in two benches, each along a side; 32 seats facing forward in the "main saloon", and another longitudinally oriented section for 16.
Principal Dimensions by Steve Llanso of Middle Run Media | |||
---|---|---|---|
Class | Branch/Q1 | Suburban/A | Suburban/A2 |
Locobase ID | 20159 | 10592 | 20036 |
Railroad | Great Western | Great Western | Great Western |
Country | Great Britain | Great Britain | Great Britain |
Whyte | 0-4-0+4T | 0-4-0+4T | 0-4-0+4T |
Number in Class | 3 | ||
Road Numbers | 81-83 | 1 | 2 |
Gauge | Std | Std | Std |
Number Built | 3 | ||
Builder | GWR - Swindon | GWR - Swindon | GWR - Swindon |
Year | 1907 | 1903 | 1905 |
Valve Gear | Walschaert | Walschaert | Walschaert |
Locomotive Length and Weight | |||
Driver Wheelbase (ft / m) | 8 / 2.44 | 8 / 2.44 | 8 / 2.44 |
Engine Wheelbase (ft / m) | 48.92 / 14.91 | 45.50 / 13.87 | 48.67 / 14.83 |
Ratio of driving wheelbase to overall engine wheelbase | 0.16 | 0.18 | 0.16 |
Overall Wheelbase (engine & tender) (ft / m) | 48.92 / 14.91 | 45.50 / 13.87 | 48.67 / 14.83 |
Axle Loading (Maximum Weight per Axle) (lbs / kg) | |||
Weight on Drivers (lbs / kg) | 56,448 / 25,604 | 60,256 / 27,332 | |
Engine Weight (lbs / kg) | 86,912 / 39,423 | 71,680 / 32,514 | 92,400 / 41,912 |
Tender Loaded Weight (lbs / kg) | |||
Total Engine and Tender Weight (lbs / kg) | |||
Tender Water Capacity (gals / ML) | 540 / 2.05 | 540 / 2.05 | 540 / 2.05 |
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) | 0.84 / 1 | 1.10 / 1 | 0.84 / 1 |
Minimum weight of rail (calculated) (lb/yd / kg/m) | |||
Geometry Relating to Tractive Effort | |||
Driver Diameter (in / mm) | 48 / 1219 | 44 / 1118 | 48 / 1219 |
Boiler Pressure (psi / kPa) | 160 / 1100 | 180 / 1240 | 160 / 1100 |
High Pressure Cylinders (dia x stroke) (in / mm) | 12" x 16" / 305x406 | 12" x 16" / 305x406 | 12" x 16" / 305x406 |
Tractive Effort (lbs / kg) | 6528 / 2961.05 | 8012 / 3634.19 | 6528 / 2961.05 |
Factor of Adhesion (Weight on Drivers/Tractive Effort) | 8.65 | 9.23 | |
Heating Ability | |||
Tubes (number - dia) (in / mm) | 420 - 1.25" / 32 | 477 - 1.125" / 29 | 462 - 1.125" / 29 |
Flues (number - dia) (in / mm) | |||
Flue/Tube length (ft / m) | 4.46 / 1.36 | 4.46 / 1.36 | |
Firebox Area (sq ft / m2) | 46.46 / 4.32 | 44.34 / 4.12 | 46.75 / 4.34 |
Grate Area (sq ft / m2) | 11.54 / 1.07 | 11.48 / 1.07 | 11.54 / 1.07 |
Evaporative Heating Surface (sq ft / m2) | 659 / 61.22 | 670 / 62.24 | 653 / 60.67 |
Superheating Surface (sq ft / m2) | |||
Combined Heating Surface (sq ft / m2) | 659 / 61.22 | 670 / 62.24 | 653 / 60.67 |
Evaporative Heating Surface/Cylinder Volume | 314.65 | 319.90 | 311.78 |
Computations Relating to Power Output (More Information) | |||
Robert LeMassena's Power Computation | 1846 | 2066 | 1846 |
Same as above plus superheater percentage | 1846 | 2066 | 1846 |
Same as above but substitute firebox area for grate area | 7434 | 7981 | 7480 |
Power L1 | 5447 | 5620 | 5419 |
Power MT |