A passenger vehicle consist includes a plurality of passenger vehicles and an electrical power transmission line interconnecting the plurality of passenger vehicles. A system for communicating data in the vehicle consist includes first unit on a first vehicle in the consist and a second unit on a second vehicle in the consist. The first and second units are electrically coupled to an electrical power transmission line in the consist that interconnections adjacent vehicles. The electrical power transmission line is an existing line used in the vehicle consist for transferring electrical power to the vehicles in the consist. The first and second units are configured to transmit and/or receive at least one of high-bandwidth data or network data over the electrical power transmission line.