Equipment racks utilizing rail engaging retaining brackets that limit chassis movement

An apparatus includes an equipment chassis configured to house electronic circuitry and to be inserted in an equipment rack between an opposed pair of rails. The equipment chassis includes a bottom face configured to rest on shelf members of the rails. The apparatus further includes a retaining bracket disposed at a side face of the equipment chassis facing one of the rails and oriented substantially perpendicular to the bottom face of the equipment chassis. The retaining bracket is configured to engage a horizontal groove in the one of the rails when the equipment chassis is inserted horizontally into the equipment rack between the rails. The retaining bracket may be configured to engage the one of the rails to limit vertical movement of the equipment chassis.