At the former, two currently little-used terminus platforms will be closed and the lines connected with the existing two tracks used by Thameslink services. King's Cross Thameslink station will be replaced by a new interchange under St Pancras station. Suburban stations and power supply systems will also be extended and upgraded. They operate on 25kV ac overhead power north of Farringdon, from where they switch to 750V dc third rail operation. Each four-car set is powered by four GEC traction motors, and can reach 100 mph.
Most trains are driver-only operated.
The fleet is also fitted with automatic train protection, which can bring a train to a halt if it passes a danger signal, but because this system does not have full approval, it is usually not used. Drivers can communicate with passengers through the train's PA system, and trains also have LED displays in each carriage, which usually show the train's destination and stopping pattern. When the network is in place, the Thameslink franchise is likely to be offered for renegotiation, and could be split among several operators. A public inquiry will be held into the overall plans, as they involve some drastic redevelopment in sensitive business and residential areas. But Railtrack hopes it can get approval in time to start physical works by the end of 2001.