Rail commuters were caught in delays stretching as long as 40 minutes, after a signalling issue blocked half of the available lines at Eagle Junction.

Queensland Rail discovered the issue shortly after 6.30am.

About 40 minutes later Translink warned all northern lines except Ferny Grove were experiencing delays, including the Airport, Caboolture, Doomben, Redcliffe Peninsula, Shorncliffe, and Sunshine Coast lines.

Engineers fixed the issue just before 8am, with trains funnelled through two of the station’s four tracks for more than an hour.

The delays affected trains travelling north and south through the major rail station.

By 10am, a Queensland Rail spokeswoman said the affected routes were still facing delays of up to 30 minutes as the network backlog cleared.

The rail authority expected there would be no impact on afternoon peak travel.