In this process for production of sleepers, the concrete is poured into the forms, compacted, and then removed from the forms only after the concrete has achieved sufficient strength in reference to the pre-stressing forces applied. These production processes include forms with up to six sleepers configured adjacently. The tendons are pre-stressed with respect to the forms. When the anchorage is released immediately before the forms are removed, the pre-stressing forces are introduced into the sleeper as a result of the direct bonding between the concrete and the tendons. The form is moved onward in carousel fashion, and can be used again for fresh concrete only after the pre-stressed sleeper has been removed from the form. This means that a great number of forms is required for this particular type of continuous production process.

In this process, the sleeper forms are arranged in lines over 100 metres in length. Special devices are used to close the ends of the forms. The pre-stressing forces are introduced into the pre-stressing tendons via abutments at the end of the pre-stressing beds. When the concrete has reached sufficient strength, the pre-stressing forces are released at these abutments, which directly introduces the forces by direct bond into the concrete of the sleeper. During the entire process, the forms remain in the pre-stressing bed. Turnout sleepers are also produced in a pre-stressing bed: but with these sleepers, pre-assembled bottom plates with the required anchoring points for the rail fastenings are mounted in the pre-stressing bed, instead of the forms for normal sleepers.

For additional information, please consult the Web site www.railone.hu.