Data from "Six Wheels Coupled Radial Tank Engines, G E Ry.", Locomotive Magazine, Volume XXI [21], No. 270 [15 February 1915) and "New Radial Tank Locomotive, GER", Locomotive Magazine, Volume XXVII [27], No 349 (15 September 2021), p. ; and Ahrons (1927).
Inside-cylinder design by AJ Hill of the Great Eastern. Ten were completed as saturated steam engines. The Belpaire firebox accentuated the stubby profile. Nine-inch (229 mm) diameter piston valves served the cylinders.
When they were taken in by the London & North Eastern after grouping, they were modified, gaining a smaller, superheated boiler See Ahrons (1927) for data
Data from "Six Wheels Coupled Radial Tank Engines, G E Ry.", Locomotive Magazine, Volume XXI [21], No. 270 [15 February 1915); Richard HN Hardy (see Locobase 2314 for a discussion of this photographer and his extensive collection of LNER images) on at [], accessed 8 May 2006 (link no longer outside paywall); and Ahrons (1927).
Inside-cylinder design by AJ Hill with nominal superheating -- this was one of two engines, the other of which was not superheated.
According to the North Norfolk Railway site, this class was "scheduled for the intensive Liverpool Street suburban services, the ñJazz' service, they replaced the 0-4-4 "Gobblers" and the "Buckjumpers". The LNER liked them so much that they built many more, the class eventually totalling 134 in number."
Photographer Hardy noted how much one thoughtful improvement could help a techy design. Discussing one of his 1943 photographs, Hardy observed: "The Gresley GE type long-valve-travel N7s were at Bradford for about eighteen months and went south much better engines. They could not run the Bradford expresses as they were shy for steam and DW Harvey was sent from Loco Running HQ at Gerrards Cross to improve them, which he did by altering the design and diameter of the blast pipe." Hardy did not know if others in the class had also been modified, but, "in my experience, they steamed pretty well."
Principal Dimensions by Steve Llanso of Middle Run Media | ||
---|---|---|
Class | L77 - saturated | L77/N7 (LNER) |
Locobase ID | 3024 | 2354 |
Railroad | Great Eastern (GER) | Great Eastern (GER) |
Country | Great Britain | Great Britain |
Whyte | 0-6-2T | 0-6-2T |
Number in Class | 11 | 12 |
Road Numbers | 1000, 1002-1011/9600, 9602-9611 | 1001/9601 |
Gauge | Std | Std |
Number Built | 11 | 12 |
Builder | Stratford Works | Stratford Works |
Year | 1914 | 1914 |
Valve Gear | Walschaert | Walschaert |
Locomotive Length and Weight | ||
Driver Wheelbase (ft / m) | 16.25 / 4.95 | 16.25 / 4.95 |
Engine Wheelbase (ft / m) | 23 / 7.01 | 23 / 7.01 |
Ratio of driving wheelbase to overall engine wheelbase | 0.71 | 0.71 |
Overall Wheelbase (engine & tender) (ft / m) | 23 | 23 / 7.01 |
Axle Loading (Maximum Weight per Axle) (lbs / kg) | 39,760 / 18,035 | |
Weight on Drivers (lbs / kg) | 110,253 / 50,010 | 110,253 / 50,010 |
Engine Weight (lbs / kg) | 137,984 / 62,589 | 137,984 / 62,589 |
Tender Loaded Weight (lbs / kg) | ||
Total Engine and Tender Weight (lbs / kg) | 137,984 / 62,589 | 137,984 / 62,589 |
Tender Water Capacity (gals / ML) | 1600 / 6.06 | 1920 / 7.27 |
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) | ||
Minimum weight of rail (calculated) (lb/yd / kg/m) | 61 / 30.50 | 61 / 30.50 |
Geometry Relating to Tractive Effort | ||
Driver Diameter (in / mm) | 58 / 1473 | 58 / 1473 |
Boiler Pressure (psi / kPa) | 180 / 1240 | 180 / 1240 |
High Pressure Cylinders (dia x stroke) (in / mm) | 18" x 24" / 457x610 | 18" x 24" / 457x610 |
Tractive Effort (lbs / kg) | 20,513 / 9304.55 | 20,513 / 9304.55 |
Factor of Adhesion (Weight on Drivers/Tractive Effort) | 5.37 | 5.37 |
Heating Ability | ||
Tubes (number - dia) (in / mm) | 282 - 1.75" / 44 | 203 - 1.75" / 44 |
Flues (number - dia) (in / mm) | 12 - 5" / 127 | |
Flue/Tube length (ft / m) | 9.92 / 3.02 | 9.92 / 3.02 |
Firebox Area (sq ft / m2) | 110.20 / 10.24 | 117.30 / 10.90 |
Grate Area (sq ft / m2) | 17.70 / 1.64 | 17.70 / 1.64 |
Evaporative Heating Surface (sq ft / m2) | 1394 / 129.51 | 1189 / 110.46 |
Superheating Surface (sq ft / m2) | 102 / 9.48 | |
Combined Heating Surface (sq ft / m2) | 1394 / 129.51 | 1291 / 119.94 |
Evaporative Heating Surface/Cylinder Volume | 197.21 | 168.21 |
Computations Relating to Power Output (More Information) | ||
Robert LeMassena's Power Computation | 3186 | 3186 |
Same as above plus superheater percentage | 3186 | 3441 |
Same as above but substitute firebox area for grate area | 19,836 | 22,803 |
Power L1 | 4788 | 6630 |
Power MT | 287.22 | 397.72 |