Production of main-track and turnout sleepers

Production of main-track sleepers takes place according to the principle of late form removal with direct bonding of the tendons. This technique guarantees a maximum of productivity and maximum quality. Since 2003, TRAVERTEC has produced turnout sleepers in a new factory in Buzau, Romania, on the basis of the long-bed principle. Beginning in early 2004, the production of main-track sleepers was relocated to this new plant as well. This integration means that we can exploit all available synergies in development and production, for the benefit of our customers.

Late form removal in the carousel system with immediate bonding of the tendons

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. In addition to forms with single sleepers, these production processes also 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.

Late form removal in the pre-stressing bed

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.

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Production of sleepers for main track

Late form removal in the carousel system: in the foreground, a sleeper form without pre-stressing tendons; in the background, sleeper forms already fitted with pre-stressing tendons. These tendons are later pre-stressed with respect to the sleeper forms.

Production of sleepers for turnouts

Late form removal in a long pre-tensioning bed: at the right, a pre-stressing bed during assembly; at the left, after completion of concreting.