Yoke

A yoke is the part of the draft system that connects the coupler, or a drawbar, to the rest of the draft gear. It is the link that ties the coupler shank to the cushioning and the car structure inside the draft sill.

Where It Sits

The yoke is a loop- or strap-shaped member that surrounds the draft gear or cushion unit and sits inside the draft sill at each end of the car. The shank of the coupler or drawbar enters one end of the yoke and is held to it by a vertical pin, the Y47 pin in the case of an F-type or EF-type coupler. The draft gear fits inside the yoke, captured between the draft stops in the sill.

What It Does

The yoke carries both draft and buff loads between the coupler and the draft gear. When the car is pulled, the coupler pulls on the yoke, the yoke compresses the draft gear against the stops, and the load is fed into the sill; when the car is pushed, buff loads pass through the same chain in the other direction. By wrapping around the draft gear, the yoke keeps the coupler, gear, and stops working as one assembly and routes the heavy in-line forces of train operation into the car body.

Inspection

A cracked, worn, or broken yoke can let the coupler pull out, so yokes and their pins are inspected closely. Condemnable conditions and wear limits for the yoke are defined in the AAR interchange rules and field manual.