ICI's main engineering facilities, located at Tunstead quarries, were known as the 'South Central Workshops'.  Contemporary with the development of the Sentinel diesel hydraulic locomotive, which was radically different to traditional diesel shunting locomotives, SCW rebuilt a former Avonside 0-4-0ST into a 0-4-0DH locomotive. Three further locomotives were rebuilt along similar lines but were based on existing diesel locos and retained the original drivelines.

By the 1970s SCW concentrated on other areas and modern proprietary locomotives were bought as second-generation replacements.