NZR UB class (Baldwin)
| NZR UB class | |
|---|---|
| Type and origin | |
| Builder | Baldwin Locomotive Works, Brooks Locomotive Works, Richmond Locomotive Works |
| Build date | 1898, 1901 |
| Total produced | 22 |
| Specifications | |
| Configuration | 4-6-0 |
| Gauge | 3 ft 6 in (1,067 mm) |
| Driver diameter | 49.125 in (1.248 m) |
| Weight on drivers | 26.4 long tons (26.8 tonnes; 29.6 short tons) |
| Locomotive and tender combined weight | 57.8 long tons (58.7 tonnes; 64.7 short tons) |
| Fuel type | Coal |
| Boiler pressure |
175 lbf/in2 (1,207 kPa) (1898) 200 psi (1,379 kPa) (1901) |
| Firegrate area | 16 sq ft (1.5 m2) |
| Heating surface: – Total | 1,324 sq ft (123.0 m2) |
| Cylinders | Two, outside |
| Cylinder size | 16 in × 20 in (406 mm × 508 mm) |
| Performance figures | |
| Tractive effort |
14,590 lbf (64.90 kN) (1898) 16,670 lbf (74.15 kN) (1901) |
| Career | |
| Operator(s) | NZR |
| Disposition | Withdrawn |
The NZR UB class were a series of Ten Wheelers built by American manufacturers around the start of the twentieth century. Two batches were built by Baldwin in 1898 and 1901 (ten each). The earlier engines had slide valves and Stephenson motion, the later had piston valves and Walschaerts valve gear, as well as a higher boiler pressure. Two additional locomotives were obtained in 1901 from ALCO, one each from Brooks and Richmond. The Brooks locomotive (#17) was heavier (30.1 LT adhesive) with attendant increase in tractive effort (18340 lbf), and had a larger grate (17 sq ft). This locomotive was very popular with crews. The Richmond locomotive had less evaporative heating surface but included a superheater. Boiler pressure was lower (180 psi) and tractive effort was marginally lower. The locomotives were initially assigned to Dunedin to Christchurch expresses and were reassigned as newer power replaced them. The last assignment for the class was on the West Coast Region.
Preservation
While they are still some Ub's dumped even at Omoto, a few from Oamaru where also dumped in the forshore, Ub 17 of (ALCO) built and 282 a Baldwin built example, both engines where recovered and later sent to Waitara to their Hooterville Heritage Charitable Trust depot, and are both awaiting restoration,
References
- W.W.Stewart, When Steam Was King, REED, 1970
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