Abstract: Ballastless railroad lines are laid on prefabricated reinforced concrete slabs, which can eliminate the need for periodic maintenance of the ballast of traditional railroad lines, such maintenance being expensive and often difficult to carry out. Prefabricated, possibly prestressed, slabs are thereby positoned upon a steel reinforced concrete block having the functions of a foundation and connector for the prefabricated slabs with the interposition of a concrete-asphalt mortar layer between the slabs and block. The slabs are secured to the foundation block either by means of two half-cylinders, forming parts of the slab structure, or by shoulders formed by upturned sides of the foundation block (tub).

Abstract: Workpieces of prestressed concrete, specifically railroad ties, are molded in a form having its bottom covered with several transversely separated templates whose outline corresponds to that of respective ties to be produced; the form is longitudinally traversed by reinforcing rods or cables attached to its ends under tension. Each template is provided with several countersunk nuts to be engaged by retaining bolts which pass through upright screw anchors with downwardly opening throats loosely occupied by internally threaded centering sleeves that come to rest on the associated template. With the form compartmented by removable spacers separating the templates, concrete is poured into each compartment and allowed to harden about the screw anchors rising therein; the retaining bolts are then withdrawn along with the spacers to provide the resulting concrete blocks with a certain mobility whereupon the tensioned reinforcing armatures are released to prestress these blocks and are subsequently cut between them.