line, pending conversion of onboard and ground-based systems. The ATC system on the Toei Shinjuku Line in use from 14 May 2005 is very similar to D-ATC. Since 18 March 2006, Digital ATC has also been enabled for Tōkaidō Shinkansen, the original Shinkansen owned by Central Japan Railway Company, replacing the old analog ATC system. D-ATC is used with the THSR 700T built for the Taiwan High Speed Rail, which opened in early January 2007. DS-ATC: Implemented on Shinkansen lines operated by JR East. Stands for Digital communication & control for Shinkansen-ATC. It is used on the Tōhoku Shinkansen, Hokkaido Shinkansen, Joetsu Shinkansen and the Hokuriku Shinkansen. RS-ATC: Used on the Tōhoku, Hokkaido, Hokuriku and Jōetsu Shinkansen at a fallback level from DS-ATC. RS-ATC is similar to GSM-R in that radio signals are used to control the speed limit on trains, as compared to trackside beacons on other types of ATC. ATC-NS: First used on the Tōkaidō Shinkansen since 2006, ATC-NS (which stands for ATC-New System), is a digital ATC system based on DS-ATC. Also used on the Taiwan High Speed Railway and the San'yō Shinkansen. KS-ATC: Used on the Kyushu Shinkansen since 2004. Stands for Kyushu Shinkansen-ATC. South Korea Several subway lines in South Korea use ATC, in some cases enhanced with ATO. Busan All lines use ATC. All lines are enhanced with ATO. Seoul Other than on Lines 1 and 2 (MELCO cars only), all lines use ATC. Line 2 (VVVF cars), Line 5 cars, Line 6 cars, Line 7 cars, and Line 8 cars have their ATC systems enhanced with ATO. Europe Denmark Denmark's system of ATC (officially designated ZUB 123) is different from that of its neighbours. From 1978 until 1987, the Swedish ATC system was trialled in Denmark, and a new Siemens-designed ATC system was implemented between 1986 and 1988. In consequence of the Sorø railway accident, which occurred in April 1988, the new system was progressively installed on all Danish main lines from the early 1990s onwards. Some trains (such as those employed on the Øresundståg service and some X 2000 trains) have both the Danish and the Swedish systems, while others (e.g. ten of the ICE-TD trains) are fitted with both the Danish and the German systems. The ZUB 123 system is now considered by Banedanmark, the Danish railway infrastructure company, to be obsolete and the entire Danish rail network is expected to