To carefully shove a locomotive or cut of cars against another standing vehicle until the couplers or buffers touch and compress. This action ensures the coupling drops into place, compresses the draft gear to allow the uncoupling lever to be pulled, or simply closes the gap between equipment before tying them down.
Heard on the job
Buffer up to those gons gently so the car knocker can drop the pin.
Also heard as
- bunch up
- couple up