Quill drive

Quill drives have been extensively used in railroad electric locomotives to connect between frame-mounted traction motors and the driven wheels.

This allows the motors to be mounted on top of the suspension system, moving independently of the wheels.

This smooths the drive from the motors and isolates them from mechanical shock.

Quill drives were used by many electric locomotives in the United States, particularly those of the Pennsylvania Railroad—their long-lasting GG1 design being perhaps the best known.

The English Electric–built NZR ED class used a quill drive, but was found to be hard on the track.