Andorra doesn’t have an airport. Even if it wanted one, there’d be nowhere to put it. But while most visitors hurtle down the motorway from Toulouse or Barcelona to reach this pint-sized Pyrenean principality, I intended to follow a more convoluted route. From the sleepy town of Villefranche-de-Conflent in southwestern France, the Ligne de Cerdagne beckoned me into the Catalan Pyrenees.
This rail journey is better known as the Train Jaune because of its canary-yellow livery. When the line was built more than a…