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.

Question: When did he drive the engine?
Self-contained rewrite: When did Casey Jones drive Engine No. 638?