Abstract: The invention relates to a prestressed concrete sleeper, having at least two sleeper sections that can be coupled or are coupled rigidly by a connection device embedded in the sleeper heads, wherein the sleeper sections each comprise a concrete in the region adjacent to the connection device which has a higher rigidity than the concrete in the other regions

Abstract: A switch cross tie is made in a mold having a base plate formed with a plurality of holes in a predetermined pattern corresponding to a particular type of concrete switch cross tie by first overlying the entire base plate of a mold with a covering sheet provided with markings in a pattern corresponding to that of the holes needed for another particular type of concrete cross ties. This covering sheet overlies and blocks all the holes formed in the base plate and it is fixed in place atop the base plate. Then the operator or a computer-guided drill press cuts through the covering sheet and into the base plate at each of the markings to form thereat a respective new hole. Each such new hole is fitted with an anchor, and the mold is filled with concrete over and around the anchors with the covering sheet blocking all the holes other than the new holes. It is important that the covering sheet be sufficiently strong to inhibit entry of concrete through it into any of the holes other than the new holes.

Abstract: A switch cross tie is made in a mold having a base plate formed with a plurality of holes in a predetermined pattern corresponding to a particular type of concrete switch cross tie by first overlying the entire base plate of a mold with a covering sheet provided with markings in a pattern corresponding to that of the holes needed for another particular type of concrete cross ties. This covering sheet overlies and blocks all the holes formed in the base plate and it is fixed in place atop the base plate. Then the operator or a computer-guided drill press cuts through the covering sheet and into the base plate at each of the markings to form thereat a respective new hole. Each such new hole is fitted with an anchor, and the mold is filled with concrete over and around the anchors with the covering sheet blocking all the holes other than the new holes. It is important that the covering sheet be sufficiently strong to inhibit entry of concrete through it into any of the holes other than the new holes.

Abstract: A prestressed concrete beam is made by first fitting the opposite ends of a group of reinforcing rods through respective holes in a pair of longitudinally spaced end plates having longitudinally confronting inner faces and opposite outer faces, then providing on each of the rods a head bearing longitudinally inward on the respective outer face, and then applying opposite outward traction to the end plates to tension the rods and filling around the rods and between the inner faces of the plates with a mass of concrete. The concrete mass is then cured and the traction on the end plates is released. Subsequently the heads of the rods are released from the plates and the plates are removed from the ends of the mass of cured concrete. The heads can be machined or burnt off, or the plate can be constructed to release them.

Abstract: In the case of certain series-produced finished parts, such as switch cross ties, the precision of the assembly of components is of decisive importance. The components should neither be damaged nor should their position be changed during assembly. During the assembly process, they have to be non-slidably fastened in the casing, at the same time the fastening is not allowed to damage finished part, respectively the component, neither during the movements occuring in the hardening process, nor during the removal of the casing from the finished part, i.e. a fastening device has also to be easily detachable.

Abstract: In casings for switch cross ties, the bottom plate 3 serves at the same time as a pattern for the position of the construction components. As a rule, a new casing is prepared for each series of cross-ties type. In small series with various positions of the construction components it is economical to use the bottom plate repeatedly. This is done by providing the bottom plate, prior to its insertion in the casing, with holes (A,B,C) for several types of finished parts, by provisionally closing the unnecessary holes by suitable means and by finding the combination of holes required for the production of a certain type of finished part through a certain searching procedure and freeing them of their provisional closing means.

Abstract: For the production of cross ties for switches, made of concrete in a prestressing fixture, a recoverable device for the emplacement of tubular components is built into the bottom of the concrete form for the tie, which comprises a pin and a nipple inserted detachably into its bottom. The nipple can be inserted into a corresponding bore of a base plate. The bore determines the position of a tube in the cross tie, has an upper and a lower stop with which it is anchored in the pin or the base plate, respectively, and can be firmly tensioned upon the base plate.