Class 185 DMU Refurbishment

Diamond Rail was contracted to deliver a full turnkey interior refurbishment for the Class 185 fleet operated by TransPennine Express and maintained by Siemens Mobility. The aim was to elevate the on-board customer experience early in the franchise while also preparing two-thirds of the fleet for potential future leasing opportunities — making this a critical mid-life overhaul for 52 three-car units.

Working closely with Siemens and Eversholt Rail, we delivered a phased, high-quality programme over 51 weeks, transforming 9,464 seats and carrying out a full redesign of the First Class interior across the fleet.

For this project, we:

• Supplied and built all First and Standard Class seating, including new foams, fire barriers, e-leather and flat cloth covers
• Developed and tested new interliners and seat designs to meet GMRT/2130 iss4 compliance
• Refinished and painted grab handles, seat shells and tray tables, including the full rework of First Class interiors
• Created new tooling, moulds and jigs for internal frame builds and extended headrests
• Managed the full logistics chain using adapted stillages and dedicated, tracked vehicles
• Delivered all quality control, documentation, and sign-off from our Sheffield facility and on-site at York depot

One of the key challenges was integrating a brand-new cutting-edge First Class seat design — featuring extended headrests, custom grab handles and e-leather upholstery — into an already tight programme with stringent safety testing and sign-off requirements. This meant that we had to engineer, test, validate and deliver a bespoke First Class product within the same timeframe as a conventional refurbishment — a task that required high levels of design control, supplier coordination, and project management. Our team excel in finding innovative solutions to challenges like this, and we were able to provide a successful outcome for our client, completing all the work within the pre-determined timeframe.