Track sleepers with identical outlines are produced as bulk goods in rigid moulds on carousel systems. Due to the low variety of elements it would make sense to use a (semi) automatic system with a high repeat accuracy, which reduces staff requirement.
Due to the short elongation, wedge anchors are out of questions because of the wedge seating loss and the associated loss of stressing force. Threaded anchors ensure a transmission of the stressing force to the mould without wedge seating loss. Paul screw jacks screw themselves onto the stressing bolts, rest against the mould, stress the spindle to the stressing force set and tighten the anchor nut. Then the machine unscrews from the spindle. The stressing technology ranges from merely manual to semiautomatic and to fully automatic systems with automatic anchor nut control. If requested, this can be logged by the system control. This equipment is available both for prestressed (late-demoulded) and post-tensioned (immediately demoulded) sleepers.
Detensioning wrenches, depending on their design, mostly unscrew several anchor nuts in a synchronized manner on both sides of the mould for a uniform application of the stressing force to the sleeper, which reduces cracking. Both manual and fully automatic machines are available for this purpose, too.
For the production of sleepers with button heading anchorage we supply manual and fully automatic button heading systems in order to provide complete prestressing steels with button heads.
Turnout sleepers as well as track sleepers are produced on long casting beds. The turnout sleeper which is uniform in cross section is particularly suited for this method; it is produced in a string and sawn to length as required. If the lengths per bed covering are known, mould end plates are used as well between the sleepers.
Due to its outline and dynamics, the track sleeper is posing special challenges to the manufacturers as regards detensioning. But this type of sleepers can also be profitably produced on long casting beds and convinces by a simple plant technology as against production in the carousel system.
Casting bed equipment:
Basic machinery equipment: