British Rail Engineering Limited Swindon Works Main Office Block, Gwr Works

The Main Office Block, part of the British Rail Engineering Limited Swindon Works (formerly the Great Western Railway Works), comprises a chief mechanical engineer's and drawing office, now serving as a works manager's office and associated offices. Constructed in the 1840s, with subsequent additions and alterations in the 1870s and 1903-8, the building is primarily built of coursed rubble stone with ashlar dressings, and features later corrugated metal roofs. It has a three-story design and initially comprised 15 window bays by 3.

The west wing, originally oriented north-south, is the oldest section, and contained Sir Daniel Gooch's office on the first floor’s north end, where the original drawing office still exists. This section retains some original ashlar and one Venetian window, initially a doorway, at its south end. An east-west wing was added in the 1870s, coinciding with the reconstruction of the west wing. The top story was added in 1903, with construction possibly completed by 1908. Sash windows with glazing bars appear, with arched heads on the ground floor and square heads above, some of which have been altered. Above the main entrance doorway, on the second floor, are two carved relief depictions of broad gauge locomotives, possibly of the Firefly Class, which were originally located in the 1843 broad gauge engine shed and relocated to this position between 1903 and 1908.

Internally, the public spaces maintain the character of a late Victorian office, with wooden and glazed screens, and two iron staircases with hardwood tread inlay. The first floor includes private offices, including the Production Manager's office, and the Works Manager’s office, which retains decorative features from the 1950s. All pargetting remains intact where concealed, as does the original fireplace. Most windows are now double-glazed with standard sashes, an unusual example of Victorian noise insulation. The top-floor drawing office is roofed with rolled bridge rails, an aesthetically pleasing feature.

Historically significant, the building served as the nerve centre of the GWR works, accommodating figures such as Gooch, Armstrong, Dean, and Churchward, and was the design hub for steam and diesel locomotive classes including the Castles, Kings, and Warships. It encapsulates the three main phases of the works’ historical development and is part of an important group of Victorian industrial buildings.