Drill Motor is a term more commonly associated with the BMT and IRT than with the IND. Both systems had wooden elevated cars whose 'gravity' type 3rd rail shoes could not reach the covered 3rd rail used on the subway lines. When a cut of these cars had to be moved over a subway route to a shop (Coney Island for example) a drill motor would be used to make the move. These locomotives had 'compromise' third rail shoes, which could reach either style of third rail. Such shoes were also used on el cars which also operated on elevated portions of the subway lines. In general, el cars were not allowed to operate underground under power and were towed through the tunnels by a drill motor.
The next stop is Washington. Change for Forest Hills Trains on the Winter St. Platform, and Everett Trains on the Summer St. Platform. This is an Ashmont train, change for Braintree at Columbia.