Geotechnical drilling under the Brisbane River has started as part of planning works for what will be a landmark bus and rail transport construction project in Queensland.

On Thursday, the Sea Lift 7 barge started geotechnical investigations for the $5 billion Underground Bus and Train project – a 5.4-kilometre tunnel located about 50 metres below the Brisbane River.

The tunnel will be 15 metres wide and will combine an underground railway and busway which will link with existing above-ground rail and bus connections at Victoria Park in the North and Dutton Park in the South and include new underground stations at Woolloongabba, George Street and Roma Street.

 Brisbane Underground Bus and Train projec

State Premier Campbell Newman said the work is the first step in the project and will involve samples gathered by drilling at least 13 holes up to 60 metres deep into the river bed.

“The drill is located on a large barge that will move locations over the next few days between Lower River Terrace Park in Kangaroo Point and the City Botanic Gardens,” Newman said.

Main Roads Minister Lawrence Springborg said the tunnel will be carved from the earth using the largest hard rock tunnel-boring machine ever used in Australia.

He says a land-based drilling program would commence at the end of the month at various locations along the proposed alignment to confirm the depth and location of the tunnel and stations.

Lord Mayor Graham Quirk said the project, which essentially replaces the former government’s Cross River Rail proposal, will double the capacity of rail and bus networks throughout the city and ease pressure on existing infrastructure.

The start of drilling follows the release earlier this week of the Terms of Reference for the project’s Environmental Impact Statement for the project.

Drilling is expected to be finished in April and construction is scheduled to begin next year following the release of the EIS later this year.

In a statement, Newman said the project would generate around 18,400 full-time jobs.