Along with “Where?”, “When?” and “What?!?”, the three most insistent questions on the lips of would-be rail travellers in southern England over the past few days have been “Why, why, why?”. Now The Sunday Telegraph has an answer, of sorts. The almost total disappearance of trains from the network serving the capital from the south and east was due, it seems, to their sophisticated computer systems, which do not agree terribly well with a blend of third-rail electrification and icy conditions. A case of the wrong type of chips, perhaps?