I want to test the ability of students to read a passage and answer questions about it. Could you please come up with a good question for the passage "18th Street has a local subway station at the crossing with Seventh Avenue, served by the 1 2 trains on the IRT Broadway – Seventh Avenue Line. There used to be an 18th Street station on the IRT Lexington Avenue Line at the crossing with Park Avenue South."? 

What business is the IRT Broadway running?