JR-Central Shinkansen Inspection Train T4 'Dr. Yellow' Completes its Final Mission

▲Chilly air envelops the wintry riverside as the T4 final inspection train passes the Fuji River. A special message appears on the side windows: 'Thank you, T4'.

On 29 January 2025, JR-Central's Shinkansen inspection train T4 'Dr. Yellow' retired from its duties. T4 had served for nearly 25 years, contributing to the Tokaido and Sanyo Shinkansen safety inspections. For the next two years, another 'Dr. Yellow', T5, owned by JR-West and identical in specifications to T4, will continue inspecting the tracks.

T4 was the first train set of Type 923, based on the previous generation 700 Series Shinkansen. T4 significantly raised the maximum speed compared to the conventional T3 'Dr. Yellow'. This enhancement allowed the train to continue inspecting without any changes for many years, even after JR-Central recently replaced all passenger trains on the Tokaido Shinkansen with the new N700A and N700S Series, which operate at approximately 285 km/h, leading to a congested train schedule. Yet, 'Dr. Yellow' operated on an exclusive, slightly slower diagram that used two regular train schedules.

Although 'Dr. Yellow' is not entirely retired at this time, each press release highlighted T4's final mission, as many people recognise the rarity of the Yellow Shinkansen.

'Dr. Yellow' was in operation every ten days for many years. However, its frequency may decrease as the other test train (N700S Series, which looks identical to standard passenger trains) is nearing completion with modifications and will soon commence its mission.