Many, many years ago, one of my friends at school was a staunch Liberal Party supporter (before they joined up with the SDP). He was a lovely lad, but his main preoccupation was railways - to the extent that he had memorised virtually all of the railway timetable in Scotland. If you wanted to know when the next train from, say, Thurso to Perth was leaving, then he was your man. Ask him about anything concerning the wider world, and he would eventually steer the conversation back to the railway network. Whenever I see Jo Swinson & Co trying to pretend that the Lib Dems have anything beyond denial to offer in the current debate on Brexit, my old friend comes inexorably to mind...