The primary objective of Eress is to develop and implement the Erex IT system, which will enable infrastructure managers to accurately bill operators for the energy consumed by their trains. Erex enables infrastructure managers to receive data from energy meters fitted to electric trains and allocate fees according to the exact amount of power consumed by the train. Currently most traction energy billing is based on estimated usage.

Eress says that Erex can be a starting point for reducing traction energy usage because it allows operators to analyse current consumption and take steps to reduce it.

Other members of the group include Banedanmark, Denmark; Infrabel, Belgium; Jernbaneverket, Norway; Trafikverket, Sweden; and Finnish transport agency Liikennevirasto.