An urban passage between main lines
Tokyo Station opened on December 20, 1914, and Keihin electric services between Tokyo and the Yokohama area began the same day. The later Keihin–Tōhoku service originated in the national railway’s reorganization of urban transport. Existing main lines served long-distance travel, while electric trains suited closer stations and frequent boarding and alighting.
Tokyo’s elevated railway had earlier origins. The Railway Board’s construction outline of 1914 recalled an urban-improvement plan in 1889 connecting Shimbashi and Ueno with a major central station. Electric services into Tokyo Station used infrastructure gradually assembled through that urban railway project. The route subsequently continued north.
Connecting civil and electrical engineering
The construction outline recorded temporary power lines supported by wooden poles when Yamanote electric services began in 1909. Steel towers and catenary equipment were then added for the Keihin trains. Eirakuchō substation supplied the station; telephones, clocks and lighting progressively joined its electrical facilities. Passenger service relied on coordinated power, communications and station infrastructure.
Different organizations shared the work. The report distinguished direct labor, contracts and materials supply. Ishikawajima and Kawasaki shipbuilding enterprises assembled steel girders, while producers elsewhere supplied bricks, cement and timber. Yoshihara, who had trained at an American company, became head of Keihin–Yamanote electrical engineering in 1912, bringing overseas experience into national railway design and construction.
Overhead lines and trains work together
Keihin electric services used 1,200-volt DC power, bogie vehicles and multiple-unit control, allowing one driver to operate powered cars throughout a train. Pantographs and catenary supported heavier traffic than earlier streetcars but required accurate installation and coordination in service.
Kobayashi’s technical history distinguishes compound catenary between Tokyo and Shinagawa from simple catenary toward Yokohama. Roller pantographs were initially used and later replaced with sliding contact types. Dedicated generating facilities at Yaguchi on the lower Tama River and substations along the line supplied power. Electrification included continuously obtaining, converting and distributing electricity as well as replacing steam traction.
Suspension six days after opening
Faults occurred during the public trial on December 18, 1914. Service nevertheless began on the twentieth, but railway authorities suspended electric operation on the twenty-sixth for modifications. Steam trains again handled Keihin traffic, and the Railway Board’s president issued a public apology. Within a week, opening celebrations gave way to questions of equipment reliability.
Onoda identifies problems with imported American roller pantographs as an important element in the failure. Electric services resumed in May 1915 after repairs. Construction completion, demonstration journeys and reliable scheduled service were separate engineering stages. Actual operation taught builders how to coordinate current collectors, overhead lines and vehicles.
Yokohama and the northern route take shape
Station arrangements at Yokohama also changed. The second Yokohama Station opened at Takashimachō in 1915, while the original became Sakuragichō, dedicated to Keihin electric services. The terminus dating from 1872 gained a different role in the new system.
The elevated route between Tokyo and Ueno opened in 1925, creating a continuous passage through central Tokyo. Electric services then expanded in stages between Tabata and Ōmiya on the Tōhoku Main Line from 1928 to 1932. Keihin services stretched into a longer north–south connection, giving residents cross-district access to work and study in Tokyo.
Longer services require coordinated equipment
Train and power standards continued changing during expansion. The Keihin Line completed conversion to 1,500-volt DC in 1928; the Chūō and Yamanote lines also adjusted voltage and collection systems. Longer routes and more trains encouraged coordination among formerly separate experimental electric sections.
The Keihin–Tōhoku Line developed through connecting tracks and stations and organizing power, trains, maintenance and timetables into sustainable daily service. Opening in 1914 was a key beginning; reaching Ōmiya in 1932 marked substantial expansion. Repeated improvements between those dates made urban electric railways a backbone of commuting.