Abstract: The present invention provides a low clearance, compact guideway, train positioning system that can be installed in close quarters alongside an existing railroad track. The system is chain driven and features an improved over/under or vertical sprocket carriage drive system in which parts normally exposed to the elements are protected while, at the same time, horizontal space requirements alongside the track are reduced. The system employs a vertically oriented chain drive which employs enclosed vertically mounted drive and idler sprocket units and a chain tube enclosing the lower chain strand which further minimizes exposure of the mechanism chain to the elements by totally enclosing the lower chain path in the over/under arrangement.

Abstract: A train positioning system for moving railroad cars by engaging bogey frames from one side includes a dog carriage guideway spaced from and parallel to a railroad track, a dog carriage mounted to operate along the guideway, a first dog pivotally attached to the dog carriage to pivot in a generally horizontal plane between a retracted position and an extended position. The first dog is positioned to engage a bogey frame in a first direction and be deflected by the bogey frame in a second direction in the extended position. A second dog may be mounted in opposed spaced relation to the first dog also to pivot in a generally horizontal plane between a retracted and an extended position. The second dog is configured to engage a bogey frame in the second direction and be deflected by the bogey frame in the first direction. A system is provided for reversibly operating the dog carriage along the guideway.

Abstract: A rail car indexer that provides a continuous transfer of the rail car bogeys from one dog to the next without ramming into the rail car axles in either the forward or rearward directions. The rail car indexer includes two parallel linearly offset progressor each of which has a barney and dog attached thereto. A center balance and back pressure bypass valve are used to control the raising of the dogs and to insure that the dogs remain in their lowered position until the proper progressor is ready to begin pulling on the rail car bogey axle. Sensors and a photo eye emitter and receiver coordinate the extension, retraction and transfer of an axle between the progressors.

Abstract: Railway car indexers are disclosed that include a high dog engaging member for engaging a bogey frame behind a railway axle. The high dog is pivotally attached to a dog carriage which is slidably inserted in an indexer track juxtaposed to the railroad track. The high dog is actuated between a raised and a lowered position by a lever arm which is pivotally attached to the dog carriage and a spring-piston cylinder connected to the high dog and the lever arm. The dog carriage is moved back and forth in the indexer track to engage the lever arm and high dog with the bogey frame to move the railway cars. In a reversing indexer, the dog carriage includes opposing high dogs for engaging the bogey frame behind either axle for moving the railway cars in either direction. The single direction or reversing direction indexers include a dog carriage on one or both sides of the railroad track.