Data from "New Tank Locomotives, North British Ry," The Locomotive Magazine, Vol XV (15 December 1909), p.233. See als Richard Marsden's LNER site -- [] (Jan 2004).
W P Reid's updating of Holmes's 1886 P class went for more power and a larger boiler operating at a higher pressure, but a smaller firebox. Thus, while the ratio between total EHS and cylinder volume remained about the same, the design accepted a shorter grate. This may have been a loading-gauge accommodation in which the overall size of the locomotive remained the same (e.g., the wheelbase was unchanged) while the boiler grew. (Later on, 12 tubes would be subtracted from the boiler and the total heating surface reduced to 1,258 sq ft.
Starting from Edinburgh and serving Glasgow, Musselborough, and North Berwick, the class eventually shedded at 5 different places. As demand for locomotives in this power class declined, the need for the G9s (as LNER had reclassified the Ms) fell as well and retirements began not long after the earlier 0-4-4Ts in Scotland were withdrawn. All twelve were deleted between 1936 and 1940.
Data from Richard Marsden's LNER site -- [] (Jan 2004) for data.
Holmes based his only passenger-locomotive design for the NBR on Drummond's earlier Class P conversion (see Locobase 5906). Locobase notes that the changes included two more firetubes, a shallower firebox with more grate area, and a slightly longer wheelbase. Reid later rebuilt the class with a boiler that used newer combination water injectors.
The dozen were delivered in two batches of six each in 1886 and 1889. Used for local passenger service, the later Ps were distributed throughout the NBR system. After the 1923 Grouping, they were classed G7 by the LNER (a lower number than the earlier G8s -- go figure). Six were soon retired in 1926-1927, the other six being deleted in 1930-1932.
Richard Marsden's LNER site -- [] (Jan 2004) for data.
Dugal Drummond introduced these high-drivered engines as 0-4-2Ts in 1877, but soon put a bogie truck under the bunker to create the 0-4-4Ts seen here.
For only about six years, these locomotives carried names. In order of their scattered NBR numbers, the 1877 name allocations were: 88 - Helensburgh, 89 - Gareloch, 157 - Dumbarton, 167 - Cardross, 314 - Craigendoran, 480 - Roseneath. In 1879, when they moved farther north, they took appropriate new names: Kirkcaldy, Ladybank, Markinch, Dundee, Lochee, and Burntisland, respectively. Four years later in 1883, their nameplates were removed. (Locobase admits to including this detail from Marsden's account because of the resonance of the twelve, short-lived names.)
Initially taking the Glasgow to Helensburgh run on the Clyde Coast, the Ps went to the Fife and Northern main lines, back to Glasgow and ultimately to Dundee (4 of the six), St. Margaret's, and Stirling. From these sheds the class was retired soon after the 1923 Grouping (when they were classed G8).
Principal Dimensions by Steve Llanso of Middle Run Media | |||
---|---|---|---|
Class | M / G9 | P / G7 | P / G8 |
Locobase ID | 5908 | 5907 | 5906 |
Railroad | North British | North British | North British |
Country | Great Britain | Great Britain | Great Britain |
Whyte | 0-4-4T | 0-4-4T | 0-4-4T |
Number in Class | 12 | 12 | 6 |
Road Numbers | 586-591 | ||
Gauge | Std | Std | Std |
Number Built | 12 | 12 | 6 |
Builder | North British | ||
Year | 1909 | 1886 | 1881 |
Valve Gear | Stephenson | Stephenson | Stephenson |
Locomotive Length and Weight | |||
Driver Wheelbase (ft / m) | 7.50 / 2.29 | 7.50 / 2.29 | 7.50 / 2.29 |
Engine Wheelbase (ft / m) | 22.25 / 6.78 | 22.25 / 6.78 | 22 / 6.71 |
Ratio of driving wheelbase to overall engine wheelbase | 0.34 | 0.34 | 0.34 |
Overall Wheelbase (engine & tender) (ft / m) | 22.25 / 6.78 | 22.25 / 6.78 | 22 / 6.71 |
Axle Loading (Maximum Weight per Axle) (lbs / kg) | |||
Weight on Drivers (lbs / kg) | |||
Engine Weight (lbs / kg) | 130,592 / 59,236 | ||
Tender Loaded Weight (lbs / kg) | |||
Total Engine and Tender Weight (lbs / kg) | |||
Tender Water Capacity (gals / ML) | 1614 / 6.11 | ||
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) | 0.90 / 1 | ||
Minimum weight of rail (calculated) (lb/yd / kg/m) | |||
Geometry Relating to Tractive Effort | |||
Driver Diameter (in / mm) | 69 / 1753 | 69 / 1753 | 69 / 1753 |
Boiler Pressure (psi / kPa) | 175 / 1210 | 150 / 1030 | 150 / 1030 |
High Pressure Cylinders (dia x stroke) (in / mm) | 18" x 26" / 457x660 | 17" x 24" / 432x610 | 17" x 24" / 432x610 |
Tractive Effort (lbs / kg) | 18,160 / 8237.25 | 12,817 / 5813.70 | 12,817 / 5813.70 |
Factor of Adhesion (Weight on Drivers/Tractive Effort) | |||
Heating Ability | |||
Tubes (number - dia) (in / mm) | 252 - 1.75" / 44 | 202 - 1.75" / 44 | 200 - 1.75" / 44 |
Flues (number - dia) (in / mm) | |||
Flue/Tube length (ft / m) | |||
Firebox Area (sq ft / m2) | 95 / 8.83 | 100 / 9.29 | 101.40 / 9.42 |
Grate Area (sq ft / m2) | 16.60 / 1.54 | 17 / 1.58 | 16.50 / 1.53 |
Evaporative Heating Surface (sq ft / m2) | 1309 / 121.65 | 1059 / 98.42 | 1051 / 97.68 |
Superheating Surface (sq ft / m2) | |||
Combined Heating Surface (sq ft / m2) | 1309 / 121.65 | 1059 / 98.42 | 1051 / 97.68 |
Evaporative Heating Surface/Cylinder Volume | 170.94 | 167.96 | 166.69 |
Computations Relating to Power Output (More Information) | |||
Robert LeMassena's Power Computation | 2905 | 2550 | 2475 |
Same as above plus superheater percentage | 2905 | 2550 | 2475 |
Same as above but substitute firebox area for grate area | 16,625 | 15,000 | 15,210 |
Power L1 | 4689 | 4265 | 4263 |
Power MT |