The company, which is expected to list before Christmas, has appointed Citigate Dewe Rogerson to run comms around the float from which it hopes to raise £15m.
TNX, whose COO is Steven Wagner, wants to use the money to roll out its 360 Onboard System, which broadcasts news, weather and ads to commuters through TVs inside carriages. It has contracts with seven train operating firms to install and run 360 OS and a contract with ITN to provide news.