I have been after one of these for a while and came across this one on E-bay for £58 so i put a wee bid in and won. I will keep my eyes open for the 4 car add on set to complete it. I was not really looking to add more Loco's to my collection as i am looking to add more track and buildings, so i guess the track will be waiting for another few weeks. There is some info below on the Doc i found on the web, makes for good reading.
TOMIX 'N' GAUGE 92227 JR923 SHINKANSEN 3 CAR SETDoctor 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 bogie's and observation blisters.
The 'Doctor' part of the name is obvious from their test and diagnostic function, and the 'Yellow' part comes from the bright yellow colour they are all painted. Some have a blue waistline stripe, some a green one. The original colour scheme of yellow with a blue stripe (applied to the Class 921 track-recording cars) was created by reversing the colours (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/168 mph on the Tōkaidō Shinkansen).
From the Japan Times
‘Dr. Yellow’ train keeps line safe, elates spotters
NAGOYA — A seven-car shinkansen line inspection train runs about once every 10 days between Tokyo and Hakata in Fukuoka Prefecture, and rail buffs who spot it claim it brings good luck.
The train has been nicknamed “Dr. Yellow” because of its colour but it is officially called a comprehensive shinkansen test train.
Nobumasa Naruchi of West Japan Railway Co.’s shinkansen management headquarters said it is “what you might call an X-ray train, in that it collects data on deflections of overhead wires and bending of the rails while running.”
The train’s job is to inspect aboveground equipment.
On Jan. 29, the Tokaido Shinkansen Line was halted in Kanagawa Prefecture when an overhead power catenary severed, apparently after being struck by an out-of-place pantograph — an accordionlike device that extends from the train to touch the wire and thus transfer electricity to the train’s electric motors.
The test train that travels the 1,174-km distance between Tokyo and Hakata is popular with rail fans. An urban legend has it happiness comes to those who spot it.
Its timetable is not published. Nevertheless, a Web site details the places and times it passes so those interested may figure out when they can see it. A cheering crowd with cameras was on hand when Dr. Yellow pulled into Shin-Osaka Station en route to Hakata in December.
All of the coaches’ windows are blocked out. Carriages six and seven house large equipment to gauge signals and electricity. A dome in coach five lets inspectors view pantograph connections.
A special platform under the floor of coach four is used to inspect the tracks.
Gear to control the dome and all data collected by the various diagnostic equipment is fed to coach three. Coach two carries a device to check wear on the overhead power cable. Signals and power are monitored in coach one.
“Based on data provided by Dr. Yellow, maintenance workers on the scene fine-tune electric wires and the rails,” Naruchi said. “That’s a rewarding job for us.”