St Blazey Roundhouse and turntable are nationally listed structures, Grade II*. Grade II* is a designation by Historic England which is described in legislation as ‘particularly important buildings of more than special interest’. Only around 5.5% of the country’s listed buildings attain a Grade II*listing. In October 2015, the condition of the Roundhouse and turntable was regarded as so poor, they were placed on the Heritage at Risk Register.

The large and well-equipped structure comprises a semi-circular roundhouse running shed of nine bays, facing onto a central turntable, with fitting and erecting shops to the rear. There were also smith’s shops, stores and offices incorporated into the range of buildings running to the south. The whole complex is of red brick. To the north is a separate carriage and wagon repair shop, also of red brick. The complex is a unique survivor of a purpose-built railway engineering works in Cornwall.

It is the sole surviving rail connected open semi-circular Roundhouse in the UK.

Architectural significance

This complex is a virtually unaltered and apparently remarkably complete example of an industrial railway terminus with good attention to architectural detail, one of only three planned groups of this type in the country, and the only semi-circular roundhouse surviving in association with an external working turntable in situ.

The St Blazey Roundhouse was designed and built in 1874 by Sir Morton Peto, one of the most notable railway building contractors and a partner in Grissell and Peto, whose contract building work included the rebuilding of the Houses of Parliament, and the clearance and foundation elements (including Nelson’s Column and the lions) of Trafalgar Square, in London.

In 2014, a revised edition of the Pevsner Guide for Cornwall describes the site as ‘proper railway architecture all in red brick with much decoration, culminating in the three-bay pilastered front of the administration block, with round-headed keyed windows and modillion parapet cornice. All very intact, including the original cast iron windows, large V-jointed doors to the engine sheds and iron trusses and column stanchions to the interior’.

The turntable is thought to be largely a 20th century replacement of the original machinery, its significance lies largely in its design and functional value in combination with the listed building, rather than in the age of its intrinsic fabric.

Evidential significance

Because of the level of its completeness, archaeological survey would be likely to reveal significant evidence of use, re-use and modification around the complex, which would provide evidence of the working conditions of the people in the area. Such a survey has yet to be undertaken.

The complex is a fundamental component of the multi-layered industrial plan-form of St Blazey, a major influence of the modern development of which its function was as a major transport node and transhipment point.

Historical significance

The historical significance of the complex lies in its origins as the main southern terminus of the Cornwall Mineral Railway, as planned by William Pease. The establishment of the railway revolutionised the industrial infrastructure of the area, rendering major components like the Carmears Incline and Viaduct, obsolete at a stroke. It has been argued that as a result of the coming of the railway led to depopulation of settlements, such as Ponts Mill, where the population fell from 0 to 11 between the 1840s and the 1880s.

Communal significance

As a local landmark (particularly the highly visible stack), a source of local historic/civic pride, the complex contributes very strongly to the sense of place for this part of St Blazey. As a major historic location of employment for the surrounding area, the Roundhouse site is likely to be a major component in local oral traditions. The turntable continues to provide essential infrastructure for the manual turning of steam locomotives when visiting Cornwall.

Historic Maps

The following Ordnance Survey 25″ maps are available to view via the National Library of Scotland. The Roundhouse and turntable are clearly visible on each sheet in the lower right hand corner:

  • 1882: Cornwall LI.2 (includes: Luxulyan; St Austell; Tywardreath)
    Surveyed: 1880
    Published: 1882
  • 1907: Cornwall LI.2 (includes: Luxulyan; St Austell; Tywardreath)
    Revised: 1905 to 1906
    Published: 1907
  • 1935: Cornwall LI.2 (includes: Luxulyan; St Austell; Tywardreath)
    Revised: 1933
    Published: 1935

(The history of the Roundhouse and turntable is work in progress, if you feel you can contribute to the history, please email