2,200-tonne railway bridge moved into place in Budapest over a single weekend

A 2,200-tonne railway bridge has been installed over Soroksari ut in Budapest using self-propelled modular transporters, allowing one of the city's major roads to reopen before the Monday morning rush hour.

The new 108 m long and 20 m wide structure forms the southern half of the future Kozvagohid railway crossing, part of the Ferencvaros-Kelenfold capacity expansion. A second, matching northern span is planned to follow in around a year.

Contractor V-HID had originally considered sliding the bridge into position using temporary support towers in the road. That approach would have required piles around 20 m deep, heavy drilling equipment and a much longer closure of Soroksari ut, followed by reinstatement works. Instead, Dutch heavy lifting specialist Mammoet proposed mounting the support masts directly onto SPMTs and moving them beneath the bridge as the structure advanced, removing the need for temporary piled foundations in the carriageway.

The bridge was assembled beside the final crossing from steel sections delivered by road. Once assembled, welded and protected against corrosion, the span was progressively moved forward until part of the structure extended in cantilever. SPMTs carrying temporary support masts were then positioned beneath it to continue the move.

The operation used 176 axle lines in total. As the bridge advanced, additional SPMT modules were lowered from the upper working level to street level using a 400-tonne mobile crane, reconfigured and driven beneath the structure. By the final stages of the move, three transporter groups, each made up of four modules carrying 12 axle lines apiece, were positioned below the bridge as it approached the abutments.

Site space was one of the main constraints. Separate areas were needed for bridge assembly, temporary masts and transporter equipment, and an old tram stop had to be removed to create sufficient room for the operation. Despite the size of the structure and the restricted urban setting, Soroksari ut was closed on Friday morning and reopened before traffic resumed on Monday.

The installation is part of the second phase of Budapest's Southern Circle Railway project between Ferencvaros and Kelenfold. The 3.68 km section is being widened from two tracks to three tracks and, over part of the route, four tracks. Seven railway bridge sites are being rebuilt and new stops are also being constructed at Kozvagohid and Nadorkert.

The northern bridge will use the same installation sequence, although Mammoet expects the operation to be more constrained because the newly installed southern structure now occupies part of the available working space.

The Budapest operation shows how construction methodology can reshape the impact of a major bridge installation. Rather than adapting the road to accommodate weeks of temporary works, the bridge and its temporary supports were made mobile, turning what could have been a prolonged urban closure into a tightly controlled weekend operation.