Main railway network - Kansen-tetsu-do-mo

...The trunk line section was determined based on the provisions of the Japan National Railways Management Reconstruction Promotion Special Measures Law (promulgated in 1980). In this law, a trunk line network is defined as a section that meets the following three criteria: (1) a section that connects cities with a population of 100,000 or more, and has a passenger density (average number of passengers per day per operating kilometer) of 4,000 or more between stations in that section, (2) a section that connects a city with a population of 100,000 or more with a passenger density of 4,000 or more between stations in that section, and (3) a section with a freight density of 4,000 tons or more. In JNR, the trunk line network and sections with a passenger density of 8,000 or more were called trunk line sections. In terms of operating kilometers, the trunk lines accounted for 55% of all JNR lines, and in terms of combined passenger and freight traffic and revenue, they accounted for more than 90% of the total, so they played an extremely important role in JNR management.

*Some of the terms mentioned in "main railway network" are explained below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…幹線系線区は，日本国有鉄道経営再建促進特別措置法(1980公布)の規定に基づき決められた。同法では(1)10万都市を相互に連絡する30kmを超える区間があり，その区間内の各駅間の旅客輸送密度(営業キロ1km当りの1日平均旅客輸送人員)が4000人以上である線区，(2)10万都市と(1)の線区とを連絡する30kmを超える区間があり，その区間内の各駅間の旅客輸送密度が4000人以上である線区，(3)貨物輸送密度が4000t以上の線区，の三つの区分に該当する線区を幹線鉄道網と呼び，この幹線鉄道網と旅客輸送密度8000人以上の線区を合わせたものを国鉄では幹線系線区と呼んだ。幹線系線区は営業キロでみると国鉄全線の55％，旅客と貨物を合わせた輸送量および収入の面でみると，いずれも国鉄全体の90％以上を占め，国鉄経営上きわめて重要な位置を占めていた。…

※「幹線鉄道網」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報