Why a slower train was chosen to save the rail network

Countries & Cities · Published 15 October 2026 Swipe more like this →

In short: In the late 1980s, British Rail faced a dilemma: build high-speed trains that were too expensive or stick with aging stock. They chose a middle path—the Class 156 Super Sprinter. By intentionally lowering the top speed, they created a reliable workhorse that prioritized reliability over raw velocity.

By the early 1980s, British Rail recognized that its first-generation diesel multiple units (DMUs) were becoming too costly to refurbish. Planners initially aimed for an ambitious new generation capable of 90 mph with acceleration matching electric trains. However, testing on the experimental Class 210 revealed these high speeds were prohibitively expensive and offered no perceivable improvement in journey times because the stations they served were spaced so closely together.

In 1983, planners pivoted to a more conservative specification. They dropped the target top speed from 90 mph to 75 mph. This shift allowed for a production model built from proven components, forecasting an availability rate of 85%. To ensure passenger comfort on longer cross-country routes, they opted for stretched coaches that provided a roomy two-by-two seating arrangement, rather than the cramped two-by-three layout found in the Class 150. While this increased weight and slightly raised fuel consumption compared to the Class 150, it remained significantly more efficient than locomotive-hauled trains.

The resulting fleet of 114 sets was built between 1987 and 1989 by Metro-Cammell's Washwood Heath works. Each coach is powered by a single six-cylinder Cummins NT855-R5 diesel engine with a Voith hydraulic transmission. While they were designed for longer journeys—evidenced by their single-leaf sliding doors—they have become versatile staples of the UK network, operating on diverse routes from the West Highland Line to East Anglia.

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