BMB Turnouts and crossovers

The Opportunity

As part of the requirements for construction the Thames Tideway Western section Tunnelling works, a rail system is required for the transportation of materials to and from the TBM. At certain points in the tunnel the transporting trucks need to pass by one another and cross. Due to the shape of the tunnel the Turnouts and Crossover sections that allow this passing are elevated up from the tunnel invert to increase width and passing space. To achieve this elevation a temporary steel structure is required to be manufactured and constructed to sympathetically load the tunnel walls using cross beams with curved end plates and decking. Each beam is shaped to gradually elevate the track level from the invert to the level required for passing and crossovers.

An enquiry was sent for the manufacture and assembly of these Turnouts and Crossovers which fortunately we were successful in winning, due to our ability not only to manufacture the steelwork but also assemble in time for the planned tunnel machine shutdown and commercial competitiveness of our submission. Fundamental to the success of this project were the following key achievements;

Manufacture

• Efficient and timely procurement from the supply chain.
• Design and detailing checks of client’s drawings. This involved laying out of every beam to ensure errors in the original design were caught before manufacture. Four such significant errors were caught.
• Optimised manufacturing techniques that include efficient usage of internal CNC cutting and drilling equipment.
• Production line mentality and planning
• In house already developed manufacture and weld procedures.
• Good communication links with client to resolve TQ’s.
• Organised production planning both in manufacture but also with assembly team and the client.

Assembly

It was agreed that due to the size of the assembled modules they should be built up at a port which is feeding tunnel segments to BMB. We visited site and agreed with the port owners where and how we would facilitate the build-up requirements. Fundamental to the success of this build up section were the following key achievements;

• Cooperative nature of Port and PSS in achieving common goal.
• Understanding of the needs of a site build up.
• Mobilisation speed.
• Already obtained skills and qualifications for lifting, welding, setting out and safety.
• Workforce flexibility.
• Production control and issue preparedness.