The Railway Nationalization Act (鉄道国有法, Tetsudō Kokuyū-hō, Act No. 17 of 1906) brought many of Japan's private railway lines under national control. The 22nd Diet of Japan passed the bill on March 27, 1906 and Emperor Meiji signed on March 30, 1906. The promulgation of the act on the Official Gazette occurred the next day. The Act was repealed by Article 110 of the Act for Enforcement of Japanese National Railways Reform Act Etc. (Act No. 93 of 1986).
The original bill which passed the House of Representatives on March 16, 1906 listed 32 private railways to be nationalized, but the House of Peers amended the bill removing 15 companies from the list on March 27, 1906 and the House of Representatives accepted this amendment the same day.
Between 1906 and 1907, 2,812 miles (4,525 km) of track were purchased from 17 private railway companies. The national railway network grew to about 4,400 miles (7,100 km) of track, and private railways were relegated to providing local and regional services.