Iconic test trains nicknamed "Doctor Yellow," used to monitor the condition of tracks and overhead wires for Tokaido and Sanyo Shinkansen lines while traveling, are set to be retired due to their aging, to the disappointment of train lovers in the country, including children.

Central Japan Railway, or JR Central, and West Japan Railway, or JR West, said Thursday that they plan to end Doctor Yellow operations in January 2025 and in 2027, respectively.

The Doctor Yellow trains, known for their bright yellow exterior with a blue stripe, are operated between Tokyo Station, one of the terminals for the Tokaido Shinkansen line, and Hakata Station in Fukuoka Prefecture, one of the terminals for the Sanyo Shinkansen line, for track and overhead wire inspections. The two high-speed train lines are connected seamlessly at Shin-Osaka Station.

JR Central and JR West currently own one Doctor Yellow train each.

The popular test Shinkansen trains are operated once about every 10 days. But their operational schedules are not made public, making it rare to see them in operation or at stations. Among train enthusiasts, it is said that a sight of Doctor Yellow will bring luck.

One of the two trains went into service in 2001 and the other in 2005.

A JR Central-owned N700S Shinkansen train, currently used for passenger service, will be equipped with inspection devices to take over the role of Doctor Yellow in and after 2027.