You're the engineer on an empty troop train in the middle of the night in 1918, headed west to pick up more soldiers meant to head off to the war in Europe. You've had little sleep but you've eaten well and taken some pills for your kidneys. Almost all of the rest of the crew are back in the caboose -- perhaps playing cards or sleeping, with no passengers to tend to. You are alone, and after a while the movement of the train rocks you right to sleep. So you don't see the circus train cars on the tracks in front of you, not until it's too late.