Det anbefales at installere ETCS i rullende materiel, der allerede er i brug, når det opgraderes med en investering på mindst ti gange omkostningerne ved at installere ETCS-udstyret i den pågældende type rullende materiel.
It is recommended to install ETCS whenever a rolling stock already in service is upgraded when this entails an investment higher than at least ten times those associated with the installation of ETCS on that specific type of rolling stock.