British train engineering specialists at Interfleet have developed one-off Smart ForFour modified to run on rails. Nicknamed the Smart forrail, the prototype is a “a fully certified mini-train.”

The smart’s tridion safety cell allows it immense strength, which underpins the forrail. No matter how simple Roger Moore made it look in his Mercedes-Benz 250 SE, removing the tyres and placing it on tracks isn’t really possible in real life – the car would fall off almost immediately.


Six months of engineering work and sophisticated CAD modelling later, the smart forrail is equipped with unique, solid steel wheels each measuring 22-inches in diameter and weighing 80 kg, allowing it the traction it needs on rails.

The agile steering, which in road use allows the smart forfour to handle as if it’s on rails, was disconnected by engineers, to allow it to handle being driven on rails. To avoid any steering movement, aluminium supports were welded between the axles meaning the wheels are locked in position.


Under close supervision, the smart forrail tentatively took to the tracks at the weekend on the privately operated Bluebell Railway – providing a few, bemused commuters the chance to avoid the congested roads without having to leave the comfort of the compact four-seater. The 10-mile stretch of railway, cutting a direct route through Sussex, represented a significant challenge for the smart forrail, and yet the smallest train on the tracks took the trip in its stride, and the regular enthusiasts (present for a model railway exhibition) somewhat by surprise.


Despite challenging engineering obstacles, the experiment steadfastly refused to come off the rails. The best of both worlds were combined – albeit briefly – to create arguably the most efficient, and fun, commuting machine in the world. Shortly after, the forrail reverted back to its forfour, road-going alter ego – content with being spectacularly efficient, fun and ideal for commuting. On tarmac.

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all images courtesy of Interfleet