Prestressed Concrete Sleepers in Mass Production – Process Reliability for High-Load Precast Concrete Components

Figure: Lara Freiburger

Fig. 1: The prestressing force is transferred from the mold to the cured concrete via the control system of the stress-relief machine. The system operates fully automatically.

Figure: Lara Freiburger

Fig. 2: The molds are filled with concrete via the large “mixing console” in front of the concrete chamber. From here, the operator can monitor this critical area and intervene if necessary.

Figure: Lara Freiburger

Fig. 3: Each individual mold is fully inspected and cleaned at least once a year before it is reused in the production process

Figure: Lara Freiburger

Fig. 4: Filling the molds with material

Figure: Lara Freiburger

Fig. 5: Measuring the sleepers at the testing station: Accuracy down to a tenth of a millimeter is crucial.

Figure: Lara Freiburger

Fig. 6: In this test, the sleeper is deliberately loaded until a crack becomes visible at a specific point. Since the sleeper is prestressed, it can be used normally after the load is removed

Figure: Lara Freiburger

Fig. 7: Loading prestressed concrete sleepers in front of the Moll Rail plant in Biebesheim

Figure: Lara Freiburger

Figure: Max Freiburger

Fig. 8: The sleeper warehouse in front of the plant in Biebesheim. The site’s annual production capacity is approximately 500,000 sleepers – the total capacity of all 13 Moll Rail production sites across six countries exceeds 2 million units

Figure: Max Freiburger

Figure: Lara Freiburger

Prestressed concrete sleepers are among the most demanding mass-produced components in the precast concrete industry. Material, geometry, prestressing, and quality assurance must all interact with great precision. Sleeper production is therefore a clear example of how mass production, automation, and quality assurance work together in the manufacture of precast concrete components subjected to high loads.

Prestressed concrete sleepers are among the most demanding mass-produced components in the precast concrete industry. At first glance, they appear to be robust standard components: approximately 2.60 m long, prestressed, and manufactured in large quantities. In reality, however, the material, geometry, prestressing, and quality assurance must all work together with great precision. For the precast concrete industry, sleeper production is therefore a clear example of how mass production, automation, and quality assurance work together for high-load components.

On the track, prestressed concrete...