Data from Bryan Attewell ([] Steam locomotive simulator (April 2000 edition), corrected and supplemented by [
], last accessed 10 May 2008. Glover (1967) says this is Sir Henry Fowler's update of a London & North Western mineral engine that used a Belpaire boiler like its predecessor. It was that engine, he says, that was the last inside-cylinder 0-8-0s produced in Great Britain.
A photograph (seen at [], visited Nov 2002) shows a stolid, straight-barrelled, high-pitched boiler with a tiny stack and dome, heavy plate frame, and 6-wheeled tender with outside springs. Heating surface area later was reduced by 32 sq ft (2.9 sq m) to 1,402 sq ft with a commensurate reduction in superheater area of 15 sq ft (1.4 sq m) to 338 sq ft.
Steamindex's compilation -- [] (seen 20 Oct 2004) -- reveals to Locobase that this class was called the "Austin Sevens". Moreover, steamindex cites Bill Aves's article "The LMS 7F 0-8-0s - 'Austin Sevens': unnecessary and Perverse? Br. Rlys ill, 1995, 4, 358-67. and summarizes: "Despite having long travel valves and inside Walschaerts valve gear and a boiler based on that of the LNWR 0-8-0s the design was unsatisfactory due to a long wheel base coupled with inferior Derby axleboxes and bearings which were always running hot. Aves argues that the LMS should have made better use of the ROD 2-8-0s which it had purchased."
WG Thorley's book A Breath of Steam is quoted about the mechanical breakdowns this class suffered: "connecting rod little end bush wear was very heavy, it was impossible to keep gudgeon pin nuts tight for more than a few days, and longitudinal fractures developed in the gudgeon pins themselves." Thorley added, however: "It redeemed itself only by good steaming qualities and efficient use of the steam when in service."
According to [] (Nov 2002, data from [
]), the production batches ran as follows:
Lot Year Engine #s
57 1928 49500-49599
71 1930 49600-49619
81 1931 49620-49659
84 1932 49660-49674
First withdrawals came in 1949 and continued until the last two retired in 1961.
Principal Dimensions by Steve Llanso of Middle Run Media | |
---|---|
Class | Class 7F |
Locobase ID | 3762 |
Railroad | LMS |
Country | Great Britain |
Whyte | 0-8-0 |
Number in Class | 175 |
Road Numbers | 9600-9774 |
Gauge | Std |
Number Built | 175 |
Builder | L&NW - Crewe |
Year | 1929 |
Valve Gear | Walschaert |
Locomotive Length and Weight | |
Driver Wheelbase (ft / m) | 18.25 / 5.56 |
Engine Wheelbase (ft / m) | 18.25 / 5.56 |
Ratio of driving wheelbase to overall engine wheelbase | 1 |
Overall Wheelbase (engine & tender) (ft / m) | |
Axle Loading (Maximum Weight per Axle) (lbs / kg) | |
Weight on Drivers (lbs / kg) | 136,080 / 61,725 |
Engine Weight (lbs / kg) | 136,080 / 61,725 |
Tender Loaded Weight (lbs / kg) | 92,288 / 41,861 |
Total Engine and Tender Weight (lbs / kg) | 228,368 / 103,586 |
Tender Water Capacity (gals / ML) | 4200 / 15.91 |
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) | 4.50 / 4.10 |
Minimum weight of rail (calculated) (lb/yd / kg/m) | 57 / 28.50 |
Geometry Relating to Tractive Effort | |
Driver Diameter (in / mm) | 56.50 / 1435 |
Boiler Pressure (psi / kPa) | 200 / 1380 |
High Pressure Cylinders (dia x stroke) (in / mm) | 19.5" x 26" / 495x660 |
Tractive Effort (lbs / kg) | 29,747 / 13493.03 |
Factor of Adhesion (Weight on Drivers/Tractive Effort) | 4.57 |
Heating Ability | |
Tubes (number - dia) (in / mm) | |
Flues (number - dia) (in / mm) | |
Flue/Tube length (ft / m) | 14.75 / 4.50 |
Firebox Area (sq ft / m2) | 150 / 13.94 |
Grate Area (sq ft / m2) | 23.50 / 2.18 |
Evaporative Heating Surface (sq ft / m2) | 1434 / 133.22 |
Superheating Surface (sq ft / m2) | 353 / 32.79 |
Combined Heating Surface (sq ft / m2) | 1787 / 166.01 |
Evaporative Heating Surface/Cylinder Volume | 159.56 |
Computations Relating to Power Output (More Information) | |
Robert LeMassena's Power Computation | 4700 |
Same as above plus superheater percentage | 5640 |
Same as above but substitute firebox area for grate area | 36,000 |
Power L1 | 11,235 |
Power MT | 728.07 |