| Caledonian Railway 0-4-4T | |
| Powertype: | Steam |
| Designer: | John F. McIntosh |
| Builddate: | 1895–1925 |
| Whytetype: | 0-4-4T |
| Driverdiameter: | 5feet |
| Locoweight: | to |
| Fueltype: | Coal |
| Cylindercount: | Two, inside |
| Cylindersize: | 18x or NaNx |
| Boilerpressure: | 180psi |
| Tractiveeffort: | 18680or |
| Operatorclass: | CR: 439 |
| Powerclass: | 2P |
| Totalproduction: | 92 |
| Disposition: | One preserved, remainder scrapped |
The Caledonian Railway 439 Class is a class of 0-4-4T steam locomotive. It was a development of earlier Caledonian Railway 0-4-4T locomotives, including the 19 Class and 92 Class, and predecessor of the 431 Class. The 439 Class was introduced by John F. McIntosh in 1900 and a modified version was introduced by William Pickersgill in 1915.
Ninety-two engines of the class were built between 1900 and 1925, a few under LMS auspices. Seventy-four Class 439s passed into British Railways ownership in 1948 and they were numbered 55159-55236 (with gaps).
The 19 and 92 Classes were originally fitted with condensing apparatus for use on Glasgow Central Low Level lines. Twenty-four of them passed into British Railways ownership and they were numbered 55119-55146 (with gaps).
In 1922 Pickersgill introduced the 431 Class with larger cylinders and a cast-iron front buffer beam for banking. This was possibly to move the centre of gravity forwards and put more weight on the driving wheels. However, it was unusual to use a large-wheeled 0-4-4T (rather than a small-wheeled 0-6-0T) for banking. The 431 Class was numbered 431–434 by the Caledonian, 15237–15240 by the LMS, and 55237–55240 by British Railways.
In 1925 the LMS introduced their own version of the 439 Class and these were numbered 55260–55269 by British Railways.
In the 431 and LMS classes, the cylinder bore was increased to, increasing the tractive effort to 19200lbf.
One example, CR 419, (later LMS number 15189, BR 55189) has been preserved and is the flagship locomotive of the Scottish Railway Preservation Society.[1]