is the same no matter if you take a bus, train or S-Train, and a 20% discount is applied when traveling outside of peak times if using Rejsekort. Both the City Pass and Copenhagen Card aimed at tourists are accepted on the system. Future A new station is scheduled to be built: Favrholm (construction started in 2022, close to Hillerød) Since 30 trains per hour per direction now run between Dybbølsbro and Svanemøllen, building a new tunnel, running north–south in densely populated areas, has been discussed. Proposals to extend the Vestbanen (West) line from Høje Taastrup to Roskilde along existing tracks, have been discussed on several occasions, and was under investigation as of 2019. Extension from Klampenborg to Elsinore (converting the Kystbane railway to S-train standard) would prove more difficult, but the issue has been mentioned. The major problem is a lack of more capacity in the central tunnel. Connecting Copenhagen Airport, Kastrup, to the network has been proposed, although it is already served by both regional trains and the Copenhagen Metro. The Danish Transport Authority (Trafikstyrelsen) has suggested converting the F-line of the S-train network to metro standard as an M5 line, The only current interchange between the F line and the metro network are Flintholm Station and Nørrebro Station. The F line is planned be driverless and 24/7 in 2024/2026. Technical overview S-trains run on standard-gauge tracks and are powered via overhead wires. The voltage is 1,500 or 1,650 volts DC (negative overhead wire), indicating that it varies considerably with the loading and distance from a feeder station. Power is drawn from the national grid through 38 feeder stations. They have to be relatively close to each other because the large currents in the overhead wires (caused by the relatively low voltage) would lead to unacceptably large transmission losses otherwise. From 1975 until 2022, the primary signalling system was a proprietary fixed-block cab signalling system called that transmitted data to the trains via low-bandwidth audio frequency induction loops between the rails. Varying the combination of frequencies allowed up to 15 different instructions or commandssuch as stops and permitted speedsto be indicated to the train. Use of the permitted speed encoding provided full supervision of train speed; when a train running under HKT control entered a block with a lower target speed than the train's current speed it would initiate service braking until the two speeds matched. This, combined