Data from [] (25 October 2003) gives details on the history of this class.
An expansion of the K class (Locobase 2392) into a Mikado wheel arrangement, whcih allowed VR to increase grate area in its Belpaire firebox. Pitching the boiler well above the running board level left open the possibility of converting the railway to standard gauge.
Designed by AE Smith, this class was produced over a 26-year period. Like the Cs and A2s, the Ns were refitted with a "Modified Front End," which reduced cylinder back pressure. And like those classes, the Ns acquired smoke deflectors to lift the smoke out of the view of the drivers. The 50 supplied from North British Locomotive in 1949-1950 featured new boilers with thermic syphons in the firebox and combustion chambers.
10 of these went to South Australian Railways in 1951 as the 750 class. There they were unpopular with their crews, according to the National Rail Museum website, because they had cramped cab dimensions compared to the home-grown Mikes.
[], accessed 15 July 2006.
Mark Bau, editor of the Victorian railways site, says the X class was delivered by Newport in several groups and in several variants over a long building period punctuated by gaps of several years. He comments: "A heavy goods loco, the X's were basically a gauge convertible C class with a decent size boiler, and a booster unit. (except X 36). They were a much respected loco by the drivers and fireman that worked them. The X's were the most powerful goods locos VR ever rostered. "
The first set of nine had round-top boilers. Eight of these were produced in 1929 and the ninth came eight years later in 1937; this one was delivered with "elephant ear" smoke deflectors that came standard for the rest of the class.
These later were rebuilt with the Belpaire firebox introduced as new-construction standard in 1938 when Newport delivered 39-45. 1942 saw three more arrive (46-48) and the class was finished with another 3 (49-51) in 1943.
The diagram shows two versions, one with a copper firebox, one with a steel one; the steel one had more heating surface; see Locobase 7689.
[], accessed 15 July 2006. See Locobase 7688 for full description of this class.
This entry shows the variant with the steel firebox that, when including the thermic syphons, added 36 sq ft to the original firebox heating surface. Locobase does not know if the steel firebox also used the Belpaire construction technique. If so, all of the X class eventually had steel fireboxes.
Principal Dimensions by Steve Llanso of Middle Run Media | |||
---|---|---|---|
Class | N | X - copper | X - steel |
Locobase ID | 2422 | 7688 | 7689 |
Railroad | Victorian Government Rlys | Victorian Government Rlys | Victorian Government Rlys |
Country | Australia | Australia | Australia |
Whyte | 2-8-2 | 2-8-2 | 2-8-2 |
Number in Class | 83 | 9 | 29 |
Road Numbers | X29 - X55 | X29 - X55 | |
Gauge | 5'3" | 5'3" | Std |
Number Built | 83 | 9 | 20 |
Builder | North British | Newport | Newport |
Year | 1925 | 1929 | 1938 |
Valve Gear | Walschaert | Walschaert | Walschaert |
Locomotive Length and Weight | |||
Driver Wheelbase (ft / m) | 15.50 / 4.72 | 17 / 5.18 | 17 / 5.18 |
Engine Wheelbase (ft / m) | 30.75 / 9.37 | 33.83 / 10.31 | 33.83 / 10.31 |
Ratio of driving wheelbase to overall engine wheelbase | 0.50 | 0.50 | 0.50 |
Overall Wheelbase (engine & tender) (ft / m) | 57.96 / 17.67 | 67.06 / 20.44 | 67.06 / 20.44 |
Axle Loading (Maximum Weight per Axle) (lbs / kg) | 30,576 / 13,869 | 43,120 / 19,559 | 43,120 / 19,559 |
Weight on Drivers (lbs / kg) | 122,416 / 55,527 | 166,320 / 75,442 | 166,320 / 75,442 |
Engine Weight (lbs / kg) | 170,240 / 77,220 | 230,496 / 104,551 | 230,496 / 104,551 |
Tender Loaded Weight (lbs / kg) | 108,976 / 49,431 | 184,576 / 83,722 | 184,576 / 83,722 |
Total Engine and Tender Weight (lbs / kg) | 279,216 / 126,651 | 415,072 / 188,273 | 415,072 / 188,273 |
Tender Water Capacity (gals / ML) | 4700 / 17.80 | 10,320 / 39.09 | 10,320 / 39.09 |
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) | 6 / 6 | 10.10 / 9 | 10.10 / 9 |
Minimum weight of rail (calculated) (lb/yd / kg/m) | 51 / 25.50 | 69 / 34.50 | 69 / 34.50 |
Geometry Relating to Tractive Effort | |||
Driver Diameter (in / mm) | 55 / 1397 | 61.50 / 1562 | 61.50 / 1562 |
Boiler Pressure (psi / kPa) | 178.40 / 1230 | 208.90 / 1440 | 208.90 / 1440 |
High Pressure Cylinders (dia x stroke) (in / mm) | 20" x 26" / 508x660 | 22" x 28" / 559x711 | 22" x 28" / 559x711 |
Tractive Effort (lbs / kg) | 28,674 / 13006.32 | 39,128 / 17748.18 | 39,128 / 17748.18 |
Factor of Adhesion (Weight on Drivers/Tractive Effort) | 4.27 | 4.25 | 4.25 |
Heating Ability | |||
Tubes (number - dia) (in / mm) | |||
Flues (number - dia) (in / mm) | |||
Flue/Tube length (ft / m) | |||
Firebox Area (sq ft / m2) | 203 / 18.87 | 215 / 19.98 | 251 / 23.33 |
Grate Area (sq ft / m2) | 31 / 2.88 | 42 / 3.90 | 42 / 3.90 |
Evaporative Heating Surface (sq ft / m2) | 1453 / 135.04 | 2566 / 238.48 | 2615 / 243.03 |
Superheating Surface (sq ft / m2) | 324 / 30.11 | 492 / 45.72 | 492 / 45.72 |
Combined Heating Surface (sq ft / m2) | 1777 / 165.15 | 3058 / 284.20 | 3107 / 288.75 |
Evaporative Heating Surface/Cylinder Volume | 153.69 | 208.29 | 212.27 |
Computations Relating to Power Output (More Information) | |||
Robert LeMassena's Power Computation | 5530 | 8774 | 8774 |
Same as above plus superheater percentage | 6526 | 10,178 | 10,178 |
Same as above but substitute firebox area for grate area | 42,734 | 52,100 | 60,823 |
Power L1 | 9313 | 14,025 | 14,423 |
Power MT | 670.88 | 743.62 | 764.72 |