Caledonian classes 113 and 72 “Dunalastair V”
London, Midland & Scottish class 3P
In 1916, William Pickersgill had 16 class 72 4-4-0 express locomotives built. From 1920, 32 more class 113 locomotives followed, which had a slightly smaller boiler and slightly larger cylinders. Technically, they could be considered the successors to McIntosh's Dunalastair range, which is why they were unofficially called “Dunalastair V”. Like their predecessors, they had the cylinders and valve gear on the inside of the frame, but a superheater straight from the factory. They reportedly performed well, which increased their lifespans. So all members of the class came to the LMS in 1923 and to the British Railways in 1948. One was scrapped in 1953 after an accident and the rest were only retired between 1959 and 1962.
Technical data
General
| Property | 113 | 72 |
|---|---|---|
| Built | 1916 | 1920-1922 |
| Manufacturers | St. Rollox, Armstrong Whitworth, North British | |
| Wheel arrangement | 4-4-0 (American) | |
| Gauge | 1,435 mm (Standard gauge) | |
Dimensions and weights
| Property | 113 | 72 |
|---|---|---|
| Wheelbase | 7.42 m | |
| Service mass | 62.2 t | |
| Adhesion mass | 40.4 t | |
| Total mass | 109.5 t | 104.2 t |
| Rigid wheelbase | 2.97 m | |
| Axle load | 20.2 t | |
| Water capacity | 19,094 l | |
| Fuel capacity | 6.7 t (coal) | |
Boiler
| Property | 113 | 72 |
|---|---|---|
| Grate area | 1.858 m² | 1.923 m² |
| Firebox surface | 13.471 m² | 13.378 m² |
| Tube heating surface | 113.342 m² | 110.09 m² |
| Evaporative heating surface | 126.813 m² | 123.468 m² |
| Superheater surface | 27.406 m² | 18.581 m² |
| Total heating surface | 154.2 m² | 142.0 m² |
Power plant
| Property | 113 | 72 |
|---|---|---|
| Driver diameter | 1,981 mm | |
| Boiler pressure | 12.4 bar | |
| Expansion type | simple expansion | |
| Cylinders | two, 508 x 660 mm | two, 521 x 660 mm |
Power
| Property | 113 | 72 |
|---|---|---|
| Power source | steam | |
| Estimated power | 783 kW (1,065 PS) | 746 kW (1,014 PS) |
| Starting effort | 90.7 kN | 95.3 kN |
Calculated values
| Property | 113 | 72 |
|---|---|---|
| Factor of adhesion | 1 : 4.37 | 1 : 4.16 |
| Optimal speed | 53 km/h | 48 km/h |
| Power-to-weight ratio | 12.6 kW/t | 12.0 kW/t |
| Heating Surface Equivalent | 249.0 m² | 227.5 m² |
| Cylinder volume/HSE | 1 : 1,075.20 | 1 : 1,236.18 |
| Adhesive weight/Total | 1 : 1.54 | |
| Tractive force/Heating surface | 1 : 12.29 | 1 : 14.02 |
| Grate area/Heating surface | 1 : 83.00 | 1 : 73.87 |
| Firebox/Tube surface | 1 : 8.41 | 1 : 8.23 |
| Total/Superheater | 1 : 4.63 | 1 : 6.64 |
