PRECAST RAILWAY UNDERPASSES PRESSED AND PULLED IN POSITION

When building railway bridges and underpasses on busy railway lines regular train services must be maintained during the construction period. This is normally obtained by making a temporary relocation of the line, or by temporarily installing steel beams to support the rails, so that excavation and construction can proceed under the steel beams. There are also some other methods, and a more advanced one is to construct the underpass beside the line, and then move it into position. This method was used in two different ways at two underpasses on the Oestfoldbanen. The smallest was a pedestrian culvert of 50 tons which was pulled into position by a rescue car in 10 minutes after the railway embankment was excavated. The biggest, a road underpass of approx. 1700 tons, was pressed through the existing embankment during a period of 3 days and nights by use of 8 hydraulic jacks of 300 tons each.