Mystery crime fiction written in the Golden Age of Murder"This offering in the British Library Crime Classics series is part of a popular subgenre of the time, called the 'railway murder mystery.' The train setting was ideal for encasing a wide variety of people in one place, giving them myriad chances for meetings and murder." —BooklistOn a dark November evening, Sir Wilfred Saxonby is travelling alone in the 5 o'clock train from Cannon Street, in a locked compartment. The train slows and stops inside a tunnel; and by the time it emerges again minutes later, Sir Wilfred has been shot dead, his heart pierced by a single bullet. Suicide seems to be the answer, even though no reason can be found. Inspector Arnold of Scotland Yard thinks again when he learns that a mysterious red light in the tunnel caused the train to slow down.Finding himself stumped by the puzzle, Arnold consults his friend Desmond Merrion, a wealthy amateur expert in criminology. To Merrion it seems that the dead man