Later this year RENFE expects to present the government with a detailed proposal to build a completely new standard gauge double-track route 728 km long linking Madrid, Zaragoza and Barcelona with the SNCF at Port Bou. Designed exclusively for use by lightweight passenger trains running at 300 km/h, the preliminary route includes 49 km on bridges and 61 km in tunnel including one under the centre of Barcelona. Technical investigations are being carried out into the use of British slab-track and overhead line equipment, as well as computer control of the driving function, using continuous communication with the trains.