Shiojiri Station in the context of Japan Freight Railway Company

The Chūō Main Line (Japanese: 中央本線, Hepburn: Chūō-honsen), commonly called the Chūō Line, is one of the major trunk railway lines in Japan. It connects Tokyo and Nagoya, although it is the slowest direct railway connection between the two cities; the coastal Tōkaidō Main Line is slightly faster, and the Tōkaidō Shinkansen is currently the fastest rail link between the cities.

The eastern portion, the Chūō East Line (中央東線, Chūō-tōsen), is operated by the East Japan Railway Company (JR East), while the western portion, the Chūō West Line (中央西線, Chūō-saisen), is operated by the Central Japan Railway Company (JR Central). The dividing point between the two companies is Shiojiri, where express trains from both operators continue north onto the Shinonoi Line towards the cities of Matsumoto and Nagano. Compared to the huge urban areas at either end of the Chūō Line, its central portion is lightly traveled; the Shiojiri-Nakatsugawa corridor is only served by one limited express and one local service per hour.

The Shinonoi Line (篠ノ井線, Shinonoi-sen) is a railway line in Nagano Prefecture, Japan, operated by the East Japan Railway Company (JR East). It connects Shinonoi Station in Nagano with Shiojiri Station in Shiojiri.

The line is a corridor between the Shinetsu Main Line and the Chūō Main Line. All the limited express trains on the Shinonoi Line come from the Chūō Main Line: Azusa from Tokyo and Shinano from Nagoya.