Data from "Steam Rail Motor Coaches", The Locomotive Magazine, Vol XII (15 November 1906), p. 186.
Like the 1903 version, this rail motor design featured the water-tube firebox design designed by Dugald Drummond. The firebox had 73 sq ft of heating surface and the 99 water tubes contributed an additional 119 sq ft
Unlike the 1903 motors, however, Drummond specifically designed this engine as a detachable power unit. Its outside cylinders drove on the bogie's rear wheels. The coach portion were of the vestibule and came as a double set. That is, the assembly had a stubby locomotive and two cars coupled through a central connection. The near car had 49 non-smoking seats and 16 smoking seats. The rear car had a guard's and luggage compartment, 32 non-smoking seats, and 16 smoking seats.
| Principal Dimensions by Steve Llanso of Middle Run Media | |
|---|---|
| Class | 736 |
| Locobase ID | 10591 |
| Railroad | London & South Western |
| Country | Great Britain |
| Whyte | 2-2-0T+4 |
| Number in Class | |
| Road Numbers | |
| Gauge | Std |
| Number Built | |
| Builder | Nine Elms |
| Year | 1906 |
| Valve Gear | Walschaert |
| Locomotive Length and Weight | |
| Driver Wheelbase (ft / m) | |
| Engine Wheelbase (ft / m) | 8 / 2.44 |
| 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) | |
| Engine Weight (lbs / kg) | 53,760 / 24,385 |
| Tender Loaded Weight (lbs / kg) | |
| Total Engine and Tender Weight (lbs / kg) | |
| Tender Water Capacity (gals / ML) | 580 / 2.20 |
| Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) | 1.10 / 1 |
| Minimum weight of rail (calculated) (lb/yd / kg/m) | |
| Geometry Relating to Tractive Effort | |
| Driver Diameter (in / mm) | 36 / 914 |
| Boiler Pressure (psi / kPa) | 150 / 1030 |
| High Pressure Cylinders (dia x stroke) (in / mm) | 10" x 14" / 254x356 |
| Tractive Effort (lbs / kg) | 4958 / 2248.91 |
| Factor of Adhesion (Weight on Drivers/Tractive Effort) | |
| Heating Ability | |
| Tubes (number - dia) (in / mm) | 216 - 1.5" / 38 |
| Flues (number - dia) (in / mm) | |
| Flue/Tube length (ft / m) | |
| Firebox Area (sq ft / m2) | 192 / 17.84 |
| Grate Area (sq ft / m2) | 9.50 / 0.88 |
| Evaporative Heating Surface (sq ft / m2) | 571 / 53.07 |
| Superheating Surface (sq ft / m2) | |
| Combined Heating Surface (sq ft / m2) | 571 / 53.07 |
| Evaporative Heating Surface/Cylinder Volume | 448.68 |
| Computations Relating to Power Output (More Information) | |
| Robert LeMassena's Power Computation | 1425 |
| Same as above plus superheater percentage | 1425 |
| Same as above but substitute firebox area for grate area | 28,800 |
| Power L1 | 10,827 |
| Power MT | |