The trio finally find a good use for caravans when they attempt to make train travel cheaper, faster and more interesting, replacing the locomotive with a specially modified car and the carriages with a series of mobile homes. Comedy star Rowan Atkinson takes the wheel of the Reasonably Priced Car, and Jeremy Clarkson takes the Jaguar XKR-S and the recently updated Nissan GT-R for a spin round the track to compare both models.