Why these powerful trains were too thirsty for their own good

Countries & Cities · Published 10 October 2026 Swipe more like this →

In short: Designed to conquer the steep hills of the TransPennine routes, the British Rail Class 185 was built with immense power. Yet, this engineering strength became a liability, leading to poor fuel efficiency. To fix it, operators had to invent a clever system to teach drivers how to cruise on fewer engines.

The Class 185 Desiro, a diesel-hydraulic multiple-unit train, was commissioned in 2003 to modernize the TransPennine Express franchise. Siemens Transportation Systems secured the £260 million contract to build 51 three-car units, with deliveries occurring between 2006 and 2007. These trains were specifically engineered to handle challenging gradients, featuring high-output Cummins QSK19 engines. However, this surplus of power proved unnecessary for the majority of the route, resulting in high fuel consumption compared to other diesel multiple units.

To mitigate these inefficiencies, Siemens and First TransPennine Express launched the 'Eco-Mode' project in mid-2007. This initiative provided drivers with route-specific advice, such as when to shut down one of the three engines while cruising. By automating engine shutdowns at depots and adopting these driving practices, the operator achieved a 7% reduction in fuel usage. Furthermore, reducing engine idling by two hours per day extended the service life of the components by an estimated 15%.

Despite their technical capabilities, the trains faced significant operational hurdles. By 2008, the fleet struggled with chronic overcrowding during peak hours, leading to calls for additional carriages that were often hindered by subsidy constraints. Passenger feedback in 2007 highlighted a divide: while users generally appreciated the comfort and cleanliness, they reported dissatisfaction with peak-time capacity and specific design elements like bin placement. Over the years, the fleet underwent various updates, including a comprehensive refurbishment completed in 2018 that added USB sockets and LED lighting to modernize the passenger experience.

The Class 185 has remained a fixture of the network, even as newer fleets were introduced. While it was originally expected that many units would be returned to the lessor, Eversholt Rail Group, as the Nova fleet arrived in 2019, operational needs forced a postponement of these plans. Today, the units continue to serve as a reminder of the complex balance between engineering for extreme terrain and the practical realities of daily commuter demand.

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