Conversation so far:
What was Casey Jones service at the World's Columbian Exposition of 1893?
Casey Jones shuttled many people from Van Buren Street to Jackson Park during the World's Columbian Exposition of 1893.
What happened at the World's Columbian Exposition of 1893 with Casey Jones?
A call was sent out for trainmen who wanted to work there. Casey Jones answered it.
When did Casey Jones drive Engine No. 638?
At the closing of the fair, No. 638 was due to be sent to Water Valley. Casey Jones asked for permission to drive the engine back to Water Valley.

Question: Which engine did he drive?
Self-contained rewrite: Which engine did Casey Jones drive?