Robbins get the double in Sydney

Two Robbins Company TBMs broke through within two days of each other at the end of July on the Epping to Chatswood Rail Line project in Sydney.

The event for contractor, Thiess – Hochtief Joint Venture (THJV), marked the completion of 50% of the tunnelling on the project that consists of 12km long twin tunnels to connect existing rail stations. The 7.2m diameter TBMs broke through on 27 and 29 July to the Epping site after being launched from the M2 shaft located near the midpoint of the tunnel route.

Each drive was 6.7km long with 51% being in curves with radii ranging from 500m to 873m. Advance rates exceeding 8m per hour have been claimed and THJV are said to be "pleased with equipment performance on the project; system availability and system utilisation are both on target."

The tunnel design requires a concrete roadbed to be cast as the tunnel is advanced. Spoil is removed by conveyor and all vehicles used are rubber tyred.

Work is now underway to get the TBMs started on the Chatswood leg of the tunnels. THJV and Robbins have taken a co-operative approach on the project and "are determined to drive production even higher on the next phase of the project."