This helper engine couples to the back of a heavy train at the bottom of a steep incline to provide the extra tractive effort needed to reach the summit. Once the train clears the grade, it uncouples on the fly and returns to the bottom of the hill to assist the next train. The practice prevents stalled trains and reduces the strain on the lead locomotive's drawgear.
The coal drag was too heavy for the ruling grade, so they called for a banker out of the yard to shove them over the summit.
Banker is a British and Commonwealth term; North American railroaders typically use pusher or helper.
Also heard as
- pusher
- helper
Related terms
Helper
An extra locomotive temporarily added to a train to provide additional power over a steep gradient.
Helper grade
A section of track steep enough to require additional locomotives to push or pull trains over the summit.
Summit
The highest elevation point on a specific railway line or mountain grade.