A crowd drive assembly for a power shovel is described. The power shovel includes a main frame, a boom connected at the lower end thereof to the main frame, a dipper handle pivotally connected to the boom and a dipper connected to the dipper handle. A rack and pinion crowd drive arrangement is provided wherein a yoke is mounted within an opening in the boom for receiving and guiding the dipper handle as it is extended and retracted by the crowd drive. A shipper shaft is journaled in the boom and extends through trunnions therein. The yoke is pivotally mounted, coaxially with the shipper shaft directly on the trunnions which are an integral part of the boom so that loads experienced by the yoke are transmitted directly to the boom and not to the shipper shaft. A removable bearing housing arrangement supports the yoke on the trunnions.