Draft Stop

A draft stop, also called a draft lug, is a stop or lug inside the draft sill that transmits coupler force into the sill structure. Draft stops come in pairs and are the points where the draft system pushes and pulls against the car's underframe.

Where It Sits

Inside the draft sill, the draft gear or cushion unit sits between two sets of stops, a front pair and a rear pair. These stops are fixed to or formed in the draft sill. The draft gear, held in its yoke, bears against the front stops in one direction of loading and the rear stops in the other, so the gear is captured between them.

What It Does

The draft stops are what actually deliver coupler loads into the car body. When the car is pulled, the draft gear presses back against one set of stops and that draft (pulling) force is fed into the draft sill; when the car is buffed or pushed, the gear presses against the other set of stops and the buff force is fed in. In between, the draft gear or cushion unit absorbs and cushions the shocks of starting, stopping, and slack action, but it is the stops that anchor those forces to the structure.

Inspection

Worn, loose, cracked, or broken draft stops let the draft gear shift and can lead to lost motion or a pulled-out draft system. The condition and wear limits of draft stops and lugs are covered by the AAR interchange rules and field manual.