Abstract: A hook-type coupler for attachment to an end of a railway transit vehicle for joining adjacent ends of a pair of railway transit vehicles wherein the hook-type coupler has a hook member pivotally mounted therein being pivotal between a latch position and an unlatch position and adapted to engage a second pivotally mounted hook member in a second hook-type coupler of compatible design and includes an uncoupling cam for forcibly pivoting the hook member to the unlatch position and a roller rotatably secured to the uncoupling cam to rollably engage a surface of the hook member when the uncoupling cam is activated through a partial rotation thereby pivoting such hook member to the unlatch position without significant sliding frictional engagement between the uncoupling cam and the hook member.