In December 2013 HEB was awarded the contract to replace Bridge 48 on the East Coast Main Trunk Line (ECMT). The bridge swap was successfully completed during a 36 hour Block of Line (BOL).

The original Bridge 48 was constructed in the 1920s to connect Waihi to Taneatua. The track was opened in 1928 and predominantly used to transport passengers around the country.

Today the ECMT is the main rail route between Tauranga and Hamilton, and is one of the country’s busiest rail freight routes.

The original bridge was a 40m long, four span steel girder bridge on hardwood timber piers and piles. Over the years KiwiRail replaced the abutments with concrete and built three new piers under the existing structure in preparation for a new bridge.

Enabling works involved modifications to the existing abutments; fabrication, installation and grouting of new concrete bolsters on top of the existing piers, together with construction of a crane pad and preparation for the BOL.

Off site, Jensen Steel fabricated the four new steel spans at 20m, 12m and two 4m lengths, from weathering steel. Each span was 5m wide and the longest span weighed 60t.

Works undertaken during the 36 hour BOL were removal of existing steel girders, excavation and cutting of existing headwalls, cut and removal of the timber piers and piles; transportation, lift and placement of the four new steel spans, grouting and welding of baseplates, and assistance to replace the ballast, sleepers and track. It was a huge undertaking with 40 staff per shift, a variety of mobile cranes, excavators, HEB Heavy Haulage trucks, light towers and a number of generators and small tools.

Please click here to view a time-lapse video of the complete bridge construction.