The new contract will see Titan sell poster and digital sites, plus sponsorships and promotions until 2017. Its original deal was due to run out in 2010.
Titan's latest win follows the recent award of advertising contracts for The O2 and the new St Pancras Eurostar hub. It also retained its Network Rail contract, covering 17 stations for the next ten years.
The contract with the South West Trains owner, Stagecoach, will see the continuation of Titan sites at 213 stations, including Clapham Junction, which houses the "colossus" backlit poster site. It plans to extend its digital screen network, Transvision, and will also replace paper 48-sheets with recyclable vinyl.
Jon Slatkin, the chief executive of Titan Outdoor, said: "We have already been working with Stagecoach on plans to maximise revenues and drive innovation."