Two MTMs were stuck in the Step 3 Man Elevator, after others exited on 2nd floor. The elevator dropped 6"" when the door closed & stopped functioning. The 2 were stuck in the elevator from 6:25 am to about 7:14 am. The fire department was called, power to the elevator shut off and the door was manually opened allowing the 2 to exit safely. MSHA was promptly notified of the event.