G&SWR 6 Class

The Glasgow and South Western Railway 6 Class was a series of inside-cylinder 4-4-0 express passenger locomotives designed by Patrick Stirling, Locomotive Superintendent of the Glasgow and South Western Railway from 1853 to 1866, and introduced in 1873 under his successor James Stirling. The class represented the continuation of Patrick Stirling's locomotive design philosophy at the G&SWR after his departure for the Great Northern Railway in 1866, where he became famous for his celebrated GNR 8-foot Single locomotives.

The Glasgow and South Western Railway operated the principal route between Glasgow St Enoch and London St Pancras via the Midland Railway's Settle and Carlisle line — the most scenic of the three Anglo-Scottish routes and, from 1876, the only one not operated by either the Caledonian or the North British. The G&SWR thus occupied a distinctive position: a medium-sized Scottish railway competing for Anglo-Scottish traffic alongside two larger and better-resourced rivals. Express locomotive performance was commercially important, and the 6 Class was part of the G&SWR's effort to provide creditable express working on the London services.

James Stirling, who succeeded his brother Patrick at the G&SWR, introduced the 6 Class in 1873 as an inside-cylinder 4-4-0 with 6 ft 6 in coupled wheels, following the configuration that was becoming the standard British express type in the early 1870s. The locomotives worked G&SWR main-line services through the 1870s and 1880s. None survives into preservation, but the class represents the G&SWR's express locomotive tradition in the period between the Stirling brothers' tenures and the Manson designs of the 1890s.