Brecknell-Willis was asked to develop a pantograph design using the same mounting positions as a conventional pantograph, albeit with two conventional pantograph arms in an opposing configuration on the same base frame. Eversholt says this provides redundancy in the event of a pantograph or catenary failure but minimises roof space compared with fitting a second pantograph. The Duplex pantograph is fitted with a fast automatic dropping device and bonded ceramic carbons.

Eversholt selected ESG as installation designer and project designer and the work was carried out by Wabtec at its Doncaster facility. The size of the new pantograph means installation involves removing a glass reinforced plastic roof panel and replacing it with a flat section. ESG carried out an ergonomic assessment of the rear cab of the locomotive focussing on the impact of the redesigned roof section, including new internal lighting and cab air-conditioning arrangements, and also developed a control system.

The existing driving controls remain unchanged and an Ethernet-based monitoring system displays the status of the Duplex pantograph on driver interfaces in both cabs of the locomotive as well as the Mk 4 driving trailers used by East Coast.

Eversholt says a test strategy has been devised to identify project risk at the design stage and allow East Coast to demonstrate the compatibility of the modified locomotive with infrastructure. The strategy includes high-voltage testing and in-service tests mentoring pantograph performance and uplift.

A full analysis of the costs of in-service delays attributable to pantograph and catenary failures was carried out prior to the start of the project.