Titan is the incumbent on the account, which is estimated to be worth £20m.
Network Rail has over 3,000 outdoor advertising sites at 2,000 locations nationwide, including London’s mainline rail stations.
The appointed agency will work on the account for five years, with the possibility of a further two.
Network Rail commercial property director David Biggs says: “We are looking for the right partner to help us develop innovations for our roadside advertising business so that we can generate ever greater commercial return.”
The company estimates that it will secure over £1bn from commercial activities in the next five years.