"He likes to keep his fire engine clean, it's a clean machine." The most famously sad Beatles song is probably Eleanor Rigby, with all its banging on about lonely people. But for my money, the saddest character in all of the Beatles' oeuvre is this fireman. He seems to be the only person working at his fire station, so it's just him and his portrait of the Queen day in and day out. He obsessively cleans his vehicle because he has nothing else to do- given the "pouring rain", his job is pretty redundant. All he has is his clean machine, which explains why its cleanliness need to be referenced twice in a single line.