Data from "Steam Motor Carriages: South-Eastern and Chatham Railway," Railway Engineer, Volume 26, No 6 (June 1905), p. 163; "Steam-Motor Carriage for Sheppey Light Railway; S E and C R Company", Engineering, (3 March 1905), p. 278.; and "Steam Railway Motor Cars with Detachable Engines", Engineering News, Volume LIII [53], No 18 (4 May 1905), p. 463.
Harry S Wainwright designed this precursor to the autotrain of the 1930s, a vehicle that combined a Belpaire-boilered steamer on the front bogie and its trailing carriage with one rear bogie. The locomotive could travel independently of the carriage, which undoubtedly made it easier to service. And it was credited with a maximum speed of 35 mph (56 kph) and an average speed, including adverse gradients, of 30 mph (48 kph).
The first example went into service on the SE&C's Sheppey Light Railway line, which had been engineered by Colonel Hollman Fred Stephens in 1896-1901 on the Isle of Kent just southeast of the Thames Estuary. The SE&C took over the line in 1905. Another went to the delightfully named Hundred of Hoo Railway, which served the Hoo Peninsula that formed the southern side of the Thames Estuary. Four more served the SE&C.
Although the steam-powered railmotors provided a useful passenger service to lightly traveled lines, they were not well-suited to handle any significant growth and certainly not big enough to provide useful freight power. By the beginning of World War I, the railmotors were out of service although the carriages carried on behind more conventional locomotive power.
| Principal Dimensions by Steve Llanso of Middle Run Media | |
|---|---|
| Class | Steam motor coach |
| Locobase ID | 8935 |
| Railroad | South Eastern & Chatham |
| Country | Great Britain |
| Whyte | 0-4-0+4T |
| Number in Class | 2 |
| Road Numbers | |
| Gauge | Std |
| Number Built | 2 |
| Builder | Kitson & Co |
| Year | 1905 |
| Valve Gear | Walschaert |
| Locomotive Length and Weight | |
| Driver Wheelbase (ft / m) | 8 / 2.44 |
| Engine Wheelbase (ft / m) | |
| Ratio of driving wheelbase to overall engine wheelbase | |
| Overall Wheelbase (engine & tender) (ft / m) | |
| Axle Loading (Maximum Weight per Axle) (lbs / kg) | |
| Weight on Drivers (lbs / kg) | 53,760 / 24,385 |
| Engine Weight (lbs / kg) | 82,880 / 37,594 |
| Tender Loaded Weight (lbs / kg) | |
| Total Engine and Tender Weight (lbs / kg) | |
| Tender Water Capacity (gals / ML) | 480 / 1.82 |
| Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) | 0.80 / 1 |
| Minimum weight of rail (calculated) (lb/yd / kg/m) | |
| Geometry Relating to Tractive Effort | |
| Driver Diameter (in / mm) | 43 / 1092 |
| Boiler Pressure (psi / kPa) | 160 / 1100 |
| High Pressure Cylinders (dia x stroke) (in / mm) | 10" x 15" / 254x381 |
| Tractive Effort (lbs / kg) | 4744 / 2151.84 |
| Factor of Adhesion (Weight on Drivers/Tractive Effort) | 11.33 |
| Heating Ability | |
| Tubes (number - dia) (in / mm) | 167 - 1.375" / 35 |
| Flues (number - dia) (in / mm) | |
| Flue/Tube length (ft / m) | 5.67 / 1.73 |
| Firebox Area (sq ft / m2) | 44.50 / 4.14 |
| Grate Area (sq ft / m2) | 8.80 / 0.82 |
| Evaporative Heating Surface (sq ft / m2) | 382 / 35.50 |
| Superheating Surface (sq ft / m2) | |
| Combined Heating Surface (sq ft / m2) | 382 / 35.50 |
| Evaporative Heating Surface/Cylinder Volume | 280.15 |
| Computations Relating to Power Output (More Information) | |
| Robert LeMassena's Power Computation | 1408 |
| Same as above plus superheater percentage | 1408 |
| Same as above but substitute firebox area for grate area | 7120 |
| Power L1 | 5084 |
| Power MT | |