Data from Richard Marsden's LNER site -- [] (15 Feb 2004). After the Y class (Locobase 5897) proved too heavy by 2 tons for the Aberdeen Dock service for which they had been bought, the GNSR bought another, scaled-down pair that easily filled the bill. The specs show them to have had the same ratios as the Ys, except for a lower factor of adhesion.
Like the Y5s, these locomotives spent their GNSR / LNER / BR years on the docks, although they too would be leased to private owners from time to time. When British Rail gave them their final set of numbers, the Z4s were numbered in sequence with the Z5s and retired about the same time. 68191 (117 / 43 / 6844 / 8191) left in 1959, while 68190 (116 / 44 / 6843 / 8190) retired a year later.
Data from Richard Marsden's LNER site -- [] (15 Feb 2004). See also "New Tank Locomotives, Great North of Scotland Ry." Locomotive Magazine, Volume XXI [21] (15 December 1915), p. 266.
Ordered for the Aberdeen Docks, these waggon-bashers weighed in at 2 tons over specifications, which prompted an order for the pair later known as Z4 (see Locobase 5898). At some later point, the weight limitation was overcome and the Z5s worked happily next to the Z4s for decades. Numbered 68193, the original 117 (32 / 6832 / 8193) left service in 1956; 68192 (116 / 30 / 6830 / 8192) retired in 1960.
Marsden notes that these locomotives would be let to private owners and occasionally even worked local goods trains (on the main line?).
Principal Dimensions by Steve Llanso of Middle Run Media | ||
---|---|---|
Class | X / Z4 | Y / Z5 |
Locobase ID | 5898 | 5897 |
Railroad | Great North of Scotland | Great North of Scotland |
Country | Great Britain | Great Britain |
Whyte | 0-4-2T | 0-4-2T |
Number in Class | 2 | 2 |
Road Numbers | 116-117 /43-44 | 116-117 /30, 32 |
Gauge | Std | Std |
Number Built | 2 | 2 |
Builder | Manning Wardle | Manning Wardle |
Year | 1915 | 1915 |
Valve Gear | Stephenson | Stephenson |
Locomotive Length and Weight | ||
Driver Wheelbase (ft / m) | 6.25 / 1.90 | |
Engine Wheelbase (ft / m) | 11.08 / 3.38 | 12.75 / 3.89 |
Ratio of driving wheelbase to overall engine wheelbase | 0.49 | |
Overall Wheelbase (engine & tender) (ft / m) | 12.75 / 3.89 | |
Axle Loading (Maximum Weight per Axle) (lbs / kg) | ||
Weight on Drivers (lbs / kg) | 51,184 / 23,217 | 62,916 / 28,538 |
Engine Weight (lbs / kg) | 51,184 / 23,217 | 62,916 / 28,538 |
Tender Loaded Weight (lbs / kg) | ||
Total Engine and Tender Weight (lbs / kg) | ||
Tender Water Capacity (gals / ML) | 480 / 1.82 | 540 / 2.05 |
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) | 1.10 / 1 | 1.10 / 1 |
Minimum weight of rail (calculated) (lb/yd / kg/m) | 43 / 21.50 | 52 / 26 |
Geometry Relating to Tractive Effort | ||
Driver Diameter (in / mm) | 42 / 1067 | 48 / 1219 |
Boiler Pressure (psi / kPa) | 150 / 1030 | 150 / 1030 |
High Pressure Cylinders (dia x stroke) (in / mm) | 13" x 20" / 330x508 | 14" x 20" / 356x508 |
Tractive Effort (lbs / kg) | 10,261 / 4654.32 | 10,413 / 4723.26 |
Factor of Adhesion (Weight on Drivers/Tractive Effort) | 4.99 | 6.04 |
Heating Ability | ||
Tubes (number - dia) (in / mm) | ||
Flues (number - dia) (in / mm) | ||
Flue/Tube length (ft / m) | ||
Firebox Area (sq ft / m2) | 48 / 4.46 | 54 / 5.02 |
Grate Area (sq ft / m2) | 7.88 / 0.73 | 9.27 / 0.86 |
Evaporative Heating Surface (sq ft / m2) | 498 / 46.28 | 600 / 55.74 |
Superheating Surface (sq ft / m2) | ||
Combined Heating Surface (sq ft / m2) | 498 / 46.28 | 600 / 55.74 |
Evaporative Heating Surface/Cylinder Volume | 162.08 | 168.38 |
Computations Relating to Power Output (More Information) | ||
Robert LeMassena's Power Computation | 1182 | 1391 |
Same as above plus superheater percentage | 1182 | 1391 |
Same as above but substitute firebox area for grate area | 7200 | 8100 |
Power L1 | 2522 | 2930 |
Power MT | 217.26 | 205.34 |