Transurban is moving towards a possible purchase of Sydney’s Cross City Tunnel (CCT) by buying the toll road’s senior debt.

Transurban on Monday announced it would buy all of the toll road’s senior debt from the Royal Bank of Scotland for $475 million.

The tunnel has proved to be a troubled asset for its owners, having twice been placed into receivership since opening in 2005.

The debt purchase is subject to regulatory approval but Transurban said it and RBS had instructed the tunnel’s receivers to continue to work towards the sale of the asset while the deal was being finalised.

Transurban chief executive Scott Charlton said the company intends to bid for the road during the sale.

“The acquisition of the senior debt in the CCT will allow us to work with the receivers to examine restructuring options for the asset and, ultimately, if successful in the sale process, put the asset onto a sustainable footing,” the company said in a statement on Monday.

Transurban already owns or part-owns of number of major toll roads in Sydney – the M2, M5, M7 motorways, the Eastern Distributor and the Lane Cove Tunnel.