Doctor Yellow

JR Central's Class 923 "Doctor Yellow" set T4 on the Sanyo Shinkansen, March 2010

Doctor Yellow (ドクターイエロー) is the nickname for the high-speed test trains that are used on the Japanese Shinkansen ("Bullet Train") dedicated express passenger train routes. The trains have special equipment on board to monitor the condition of the track and overhead wire, including special instrumented bogies and observation blisters.

The "Doctor" part of the name is from their test and diagnostic function, and the "Yellow" part comes from the bright yellow color they are all painted. Some have a blue waistline stripe, some a green one. The original color scheme of yellow with a blue stripe (applied to the Class 921 track-recording cars) was created by reversing the colors (blue with yellow stripe) used on 1,067 mm (3 ft 6 in) narrow-gauge track-recording cars.

In build and appearance, they are very similar to production, passenger carrying Shinkansen trains, and line inspection is carried out at full line speed (i.e. up to 270 km/h or 168 mph on the Tōkaidō Shinkansen).

List of Doctor Yellow trains past and present

For Tōkaidō and Sanyō Shinkansen

• Non-powered track recording cars (Yellow with blue stripe):
  • 921-1: Built in 1962 (initially numbered 4001), and withdrawn in 1980.
  • 921-2: Converted in 1964 from former MaRoNeFu 29-11 sleeping car, and withdrawn in 1976.
• 0 series type (Yellow with blue stripe):
  • 922-0 (Set T1): 4-car set converted in 1964 from the prototype set (class 1000 Set B) built in 1961, and withdrawn in 1976.
  • 922-10 (Set T2): 7-car set owned by JR Central. Built in 1974 and withdrawn in 2001.
  • 922-20 (Set T3): 7-car set owned by JR West. Built in 1979 and withdrawn in 2005.
• 700 series type (Yellow with blue stripe):
  • 923 (Set T4): 7-car set owned by JR Central. Delivered in 2000.
  • 923-3000 (Set T5): 7-car set owned by JR West. Delivered in 2005.

• 
  JR Central Class 922 set T2, October 1998
• 
  JR West Class 922 set T3, October 2004
• 
  JR Central Class 923 set T4, July 2008
• 
  JR West Class 923 set T5, July 2008

For Tōhoku, Jōetsu, Hokuriku, Yamagata, and Akita Shinkansen

• 200 series type (Yellow with green stripe):
  • 925/0 (Set S1): 7-car set owned by JR East. Delivered in 1979 and withdrawn in 2001.
  • 925/10 (Set S2): 7-car set owned by JR East. Converted from former Class 962 test train in 1982 and withdrawn in 2002.
• E3 series type (White with red stripe)
  • E926 (Set S51): "East i" 6-car set owned by JR East. Delivered in August 2001.

• 
  Class 925 set S1, 1987
• 
  Class 925-10 set S2, September 2002
• 
  E926 East i train at Omiya Station, May 2001

Preserved examples

Preserved Doctor Yellow car 922-26 inside the SCMaglev and Railway Park, March 2011

• 922-26 (ex-set T3, built 1979 by Hitachi) at SCMaglev and Railway Park, Nagoya, since March 2011

See also

• New Measurement Train, a British train used to assess the condition of track
• TGV Iris 320, the French counterpart of Doctor Yellow, used to monitor the condition of the French tracks (mainly the high-speed railways LGV) used by high-speed trains.