Abstract: The disclosed technology generally describes efficient garbage collection operations based on chunk filters (e.g., Bloom filters) maintained in association with object table partitions (e.g., trees). When an object update impacts a chunk, a corresponding chunk filter is updated, using the chunk's identifier as a chunk filter key by hashing the chunk identifier into chunk filter locations and setting bits at those locations. When garbage collection occurs, a garbage collection candidate chunk's identifier is similarly hashed to read the bit values at those locations in the chunk filters for the partitions. If any bit is zero, the chunk is definitely not in use in a partition; if no chunk filter for any partition indicates the candidate chunk is possibly in use, the chunk is garbage collected without tree scanning. If tree scanning is needed, only the partition(s) with an associated chunk filter that indicates “possibly in use” need to be scanned.

Abstract: The disclosed technology generally describes efficient garbage collection operations based on chunk filters (e.g., Bloom filters) maintained in association with object table partitions (e.g., trees). When an object update impacts a chunk, a corresponding chunk filter is updated, using the chunk's identifier as a chunk filter key by hashing the chunk identifier into chunk filter locations and setting bits at those locations. When garbage collection occurs, a garbage collection candidate chunk's identifier is similarly hashed to read the bit values at those locations in the chunk filters for the partitions. If any bit is zero, the chunk is definitely not in use in a partition; if no chunk filter for any partition indicates the candidate chunk is possibly in use, the chunk is garbage collected without tree scanning. If tree scanning is needed, only the partition(s) with an associated chunk filter that indicates “possibly in use” need to be scanned.

Abstract: A preferred embodiment is directed to a finger for use in a rail plate inserter machine workhead and for positioning a rail plate predisposed on a rail tie under a rail, having a planar body having an upper arm with a hook-shaped end and including an opening for accommodating a spring, the end being configured for being contacted by a bar operatively associated with a finger lift assembly; a lower arm having a depending tip; and a middle portion joining the upper and lower arms to define an obtuse angle.

Abstract: A preferred embodiment is directed to a finger for use in a rail plate inserter machine workhead and for positioning a rail plate predisposed on a rail tie under a rail, having a planar body having an upper arm with a hook-shaped end and including an opening for accommodating a spring, the end being configured for being contacted by a bar operatively associated with a finger lift assembly; a lower arm having a depending tip; and a middle portion joining the upper and lower arms to define an obtuse angle.

Abstract: A workhead assembly for use with a rail maintenance machine having a workhead assembly for use with a rail maintenance machine having a rail lifter and configured for movement relative to a railroad track having a pair of rails, the workhead assembly constructed and arranged for positioning a tie plate predisposed on a rail tie, including a workhead body connected to the machine; a centering apparatus on the body constructed and arranged for centering the workhead over the rail tie; a squaring apparatus on the body constructed and arranged for squaring the tie plate on the rail tie; and a pusher assembly on the body for positioning the tie plate under a selected one of the rails being lifted by the rail lifter, and including at least one plate engaging finger constructed and arranged for engaging the tie plate.