Perth-based Stagecoach and Aberdeen-based FirstGroup have been shortlisted to compete for the next South Western rail franchise in June 2017.
Stagecoach has operated the network under the South West Trains brand since 1996.
The current franchise covers routes between London Waterloo, Reading, Bristol, Exeter, Weymouth and Portsmouth. It also includes the Isle of Wight.
Stagecoach said almost 1,700 trains a day serve more than 200 stations on the franchise and about 14% of all passenger journeys in the UK are made on the South Western network.
The UK Department for Transport has started consulting with passengers, businesses and local councils about the new South Western franchise.
Stagecoach said the Department for Transport has yet to confirm the length of the new contract and that the consultations run until February 9, 2016.
“We are proud to have been trusted to run the South Western network for the past 20 years,” said Stagecoach chief executive Martin Griffith.
“The continuity of one operator understanding and serving passengers and local communities has been key, helping transform the network and attract millions of new customers to rail travel.
“Over the past two decades, we have introduced an entire new fleet of trains and invested in other major passenger improvements.
“We have worked in close partnership with Network Rail to deliver a more integrated railway. Our expertise has helped government develop a long-term vision for our rail network.
“We have also returned hundreds of millions of pounds to the taxpayer to reinvest in public services.
“But more work needs to be done. The next franchise requires a transport operator which fully understands this complex network, grasps the massive challenges ahead, and has a track-record of delivery and working effectively with industry partners.
“Our experience means we are well placed to see that job through.”
Steve Montgomery, First Rail managing director said: “We have extensive experience of running commuter, inter-urban, regional and long distance services — such as those that make up the South Western franchise — and a strong track record in delivering passenger growth, as well as capacity and infrastructure upgrades, on our Great Western Railway and First TransPennine Express networks.
“The South Western franchise plays a crucial role in keeping people moving and communities prospering across the region. We are developing an innovative and value for money proposal that will deliver better connectivity and significant improvements for customers. We look forward to the publication of further details by the DfT.”