101 series
JNR 6-car set at Asaka Station on the Hanwa Line, 1978
In service	1957–2003
Replaced	72 series
Constructed	1957–1969
Entered service	December 1957
Scrapped	1987–2014 (not all parts are fully scrapped, other remaining parts such as pantographs are still in use in other rolling stocks such as 121 series/7200 series[1] & remodeled 145 series converted from old 101 series EMUs)
Number built	1,535 vehicles
Number in service	None (44 vehicles being converted into 145 series multiple locomotive)
Number preserved	2 vehicles
Number scrapped	1,489 vehicles
Successor	103 series, 205 series, 207 series
Formation	2, 3, 6, 7, 8 or 10 cars per trainset
Operators	JNR (1957–1987) JR East (1987–2003) JR-West (1987–1992) Chichibu Railway (1986–2014)
Specifications
Car body construction	Steel
Car length	20,000 mm (65 ft 7 in)
Width	2,879 mm (9 ft 5.3 in)
Doors	4 pairs per side
Maximum speed	100 km/h (62 mph)
Traction system	Resistor control
Traction motors	MT46
Power output	100 kW (134 hp)
Acceleration	2.0 km/(h⋅s) (1.2 mph/s) (7-car formation) 3.2 km/(h⋅s) (2.0 mph/s) (all motored cars)
Deceleration	3.0 km/(h⋅s) (1.9 mph/s) (service, 7-car set) 3.5 km/(h⋅s) (2.2 mph/s) (emergency)
Electric system(s)	1,500 V DC overhead catenary
Current collector(s)	Pantograph
Bogies	DT21, DT21T, TR64
Track gauge	1,067 mm (3 ft 6 in)

The 101 series (101系, 101-kei) was a DC electric multiple unit (EMU) commuter train type introduced in 1957 by Japanese National Railways (JNR), and formerly operated by East Japan Railway Company (JR East) and West Japan Railway Company (JR-West). The last remaining trains were withdrawn in November 2003.

The prototype 101 series set was delivered in June 1957, as a 10-car (4+6-car) set classified as 90 series with all cars motored. Cab cars were numbered MoHa 90500 to 90503, and the intermediate cars were numbered MoHa 90000 to 90005. Production sets were delivered from March 1958, differing visually from the prototype in having exposed rain gutters along the top of each car. The 90 series was reclassified as 101 series from 1959, with the prototype set cars numbered in the 900 subseries. The prototype set was modified in 1962 to bring it up to production set standards.^[2]

101 series trains operated on the following lines.

• Chūō Line (Rapid) (1957-1985)
• Itsukaichi Line (1978-1985)
• Keihin-Tohoku Line (1970-1978)
• Musashino Line (1973-1986)
• Nambu Line (1969-1991 for commuter rail services; 1980 - November 2003 for Branch line services)
• Chūō-Sōbu Line (1963-1988)
• Tsurumi Line (1980-1992)
• Yamanote Line (1961-1968)
• Akabane Line (Now Saikyō Line) (1967-1978)

• Kansai Main Line
• Katamachi Line (1976-1992)
• Osaka Loop Line (1964-1991)
• Sakurajima Line (1961-1991)

• 
  JNR 101 series EMU approaching Kinshicho Station at Chuo-Sobu Line, August 1978
• 
  A JNR 101 series EMU leaving Katamachi Station on the Katamachi Line, 1985
• 
  JR East 3-car Tsurumi Line set at Musashi-Shiraishi Station, circa December 1990
• 
  A JR East 2-car Nambu Branchline set at Shitte Station in July 2002
• 
  Last standing 101 series with "Sayonara" head mark on its last run on Nambu Branch Line Services in December 2003

A number of former 101 series trains were sold to the private railway operator Chichibu Railway in Saitama Prefecture in 1986, where they operated as 3-car 1000 series sets until March 2014.

• 
  A Chichibu Railway 1000 series set in January 2008
• 
  Chichibu Railway 1000 series sets in "revival" JNR liveries in December 2007

• KuMoHa 101-902 is preserved at The Railway Museum in Saitama, previously preserved at JR East's Tokyo General Rolling Stock Center.^[3]
• A 101 series mock-up car is exhibited at the Kyoto Railway Museum.^[4]

• 
  KuMoHa 101-902 at Tokyo General Rolling Stock Center, August 2005
• 
  Mock-up of a 101 series at the Kyoto Railway Museum, April 2017

• "JR East 101 series". jreast.co.jp (in Japanese). Archived from the original on 4 February 2004. Retrieved 27 October 2011.