The campaign, created by DLKW Lowe, broke this week. It includes a TV ad and outdoor activity across 800 sites in the UK, including all major rail stations in London, Manchester, Liverpool and Edinburgh. Media buying is handled by Vizeum.
The TV ad shows a herd of sheep queuing to buy tickets at a station, running up and down escalators and bumping in to each other on a platform, while a man walks in to the station and straight onto the train.
The ad highlights the fact that the man has made a saving on his train ticket by buying it in advance through the website, and encourages consumers to download thetrainline.com app.
The app allows people to buy tickets closer to the time of travel than on thetrainline.com.
Iain Hildreth, director of marketing, thetrainline.com, said: "Thetrainline.com website is well known among UK train travellers as the place to go to save money on train tickets, but not everyone knows that we can also help our customers to save time too with our new mobile app.
"This campaign is designed to let train travellers know that they can use our free mobile app to buy tickets or just check train times and to let them know that all they need to do to download it is text 'train' to 86688'."
The app is compatible with iPhone, Nokia, Samsung, Sony-Ericsson, Android and Blackberry smartphones.