A journey from the Mexican border at San Diego, following the Californian coast north to the city of San Luis Obispo, aboard the aptly named Pacific Surfliner. Pulled by a gleaming Siemens Charger locomotive, the rake of five double-deck coaches takes viewers on a 350-mile trip.

This week's rail journey is one like few others. From the Quinta de Vargellas, a vineyard that has been making one of Britain's favourite after-dinner tipples for centuries — port — we travel down the line that once transported it to the city that gave it its name, Porto.