Go-Ahead has urged the Government to speed up the tender process for the Thameslink rail franchise.
The transport group said it remained keen to operate the north London-south London line, which is expected to be up for grabs in the spring. The process was delayed last year in the wake of the FirstGroup/Virgin Rail debacle.
Go-Ahead's chief executive David Brown said: "Our current three franchises carry almost a third of all passengers in England, and we have 16 years' experience of managing complex commuter franchises and delivering industry-leading projects.
"We remain on the short list for the Thameslink franchise, and we urge the Department for Transport to begin the tender process over the coming months to ensure that the Thameslink programme is delivered on schedule."
Go-Ahead saw pre-tax profits dip 1.8 per cent to £43.2m during the six months ending 29 December. The company, which operates the Southern, Southeastern and London Midland rail franchises, said profits at its rail unit fell 14.5 per cent to £14.1m after operational problems at Southern and London Midland.
However, profits in its core bus division rose 5.4 per cent to £37.1m. The group said it was on track to grow profits at the unit to £100m by 2016.