| LNWR Precursor Tank | |
|---|---|
| Precursor tank Nº 528 | |
| Power type | Steam |
| Designer | George Whale |
| Build date | 1906–1909 |
| Total produced | 50 |
| Configuration | 4-4-2T |
| UIC classification | 2′B1 2t |
| Gauge | 4 ft 8 1⁄2 in (1,435 mm) |
| Leading wheel diameter |
First 30: 3 ft 9 in (1.143 m) Last 20: 3 ft 3 in (0.991 m) |
| Driver diameter | 6 ft 3 in (1.905 m) |
| Trailing wheel diameter |
First 30: 3 ft 9 in (1.143 m) Last 20: 3 ft 3 in (0.991 m) |
| Locomotive weight | 74 tons 15 cwt (167,400 lb or 75.9 t) |
| Boiler pressure | 175 psi (1.21 MPa) |
| Cylinders | Two, inside |
| Cylinder size | 19 × 26 in (483 × 660 mm) |
| Valve gear | Joy |
| Tractive effort | 15,216 lbf (67.68 kN) |
| Career | LNWR » LMS |
| Power class | LMS: 2P |
| Withdrawn | 1927–1940 |
| Disposition | All scrapped |
The London and North Western Railway (LNWR) Precursor Tank Class was a class of 4-4-2 tank steam locomotives. Fifty were built to the design of George Whale between 1906 and 1909, being a tank engine version of his Precursor Class.
The first thirty had 3 ft 9 in (1.143 m) carrying wheels, the latter twenty had 3 ft 3 in (0.991 m) carrying wheels. The LNWR reused numbers from withdrawn locomotives, so the numbering system was completely haphazard. The 3 ft 9 in engines were numbered by 528, 531, 784, 1295, 1305, 1981–1985, 97, 111, 181, 196, 562, 616, 803, 1356, 1508, 2210, 139, 653, 834, 874, 1506, 1572, 1589, 1671, 1714, and 2165. The 3 ft 3 in engines were numbered 44, 527, 612, 762, 827, 875, 1427, 1764, 2196, 2446, 920, 935, 1164, 1219, 1523, 1536, 1551, 2077, 2223 and 2228.
All fifty passed into LMS ownership in 1923. The LMS gave them the power classification 2P. The LMS also renumbered them into solid block of numbers: 6780–6809 for the 3 ft 9 in engines and 6810–6829 for the 3 ft 3 in engines, in the order given above.
They were withdrawn between 1927 and 1940. None were preserved.