The Japan Railways Group, more commonly known as the or simply JR, consists of seven for-profit stock companies that took over most of the assets and operations of the government-owned Japanese National Railways (JNR) on April 1, 1987. Most of the liability of the JNR was assumed by the JNR Settlement Corporation. The JR Group lies at the heart of Japan's railway network, operating a large proportion of intercity rail service (including the Shinkansen high-speed rail lines) and commuter rail service. JR Hokkaido, JR Shikoku, and JR Freight (JRF) are governed by the , also known as the JR Companies Act, and are under the control of the public Japan Railway Construction, Transport and Technology Agency (JRTT), while JR East, JR Central, JR West, and JR Kyushu are completely floated in the stock market; in addition, JR East, JR Central and JR West are constituents of the Nikkei 225 and TOPIX 100 indices. Because the railways used to be owned by the government, Japanese people generally make a distinction between JR railways (including former JR lines that are now third sector) and other private railways, and JR railways are almost always denoted differently from other private railways when shown on maps. Companies The Japan Railways Group consists of seven operating companies and two other companies that do not provide rail service. The operating companies are organized into six passenger operators and a nationwide freight operator. Unlike some other groups of companies, the JR Group is made up of independent companies, and it does not have group headquarters or a holding company to set the overall business policy. The six passenger railways of the JR Group are separated by region. Nearly all their services are within the prescribed geographic area. However, some long-distance operations extend beyond the boundaries. The Shirasagi train service between and , for instance, uses JR West rolling stock but the segment of track between Nagoya and is owned by JR Central, whose crew manage the train on that section. Japan Freight Railway Company operates all freight service on the network previously owned by JNR. In addition, the group includes two non-operating companies. These are the Railway Technical Research Institute and Railway Information Systems Co., Ltd. To cover various non-railway business areas, each regional operator in the JR Group has its own group of subsidiary companies with names like "JR East Group" and "JR Shikoku Group." Network JR