Located in Shinagawa Ward, Tokyo, the Ōi Rolling Stock Yard (大井車両基地) is one of JR Central’s major train depots, primarily responsible for the maintenance and storage of Shinkansen, including the iconic "Doctor Yellow" diagnostic train. Positioned between Tokyo and Shin-Yokohama on the Tokaidō Shinkansen line, this facility plays a crucial role in keeping Japan’s high-speed rail system running smoothly and safely. While it's not open to the public, the facility has gained popularity among railway enthusiasts and photographers for its unique sightings and occasional open events.

The depot stretches over a vast area and is surrounded by multiple train tracks, with its own turnouts and dedicated maintenance platforms. It houses not only regular N700 series Shinkansen but also the rare Doctor Yellow, a bright yellow test train used to monitor track alignment and overhead wire conditions. Because the Doctor Yellow does not follow a regular schedule, sightings of it are considered lucky, and trainspotters often gather around the depot's perimeter for a chance to capture it. The depot is strategically located near the Ōi Futo (大井埠頭) area, an industrial and logistics hub, and borders JR Freight’s container yards, adding to the visual complexity of the surroundings.

Though access to the interior is restricted, the facility becomes accessible to the public during rare open-day events such as the Shinkansen Festival (新幹線なるほど発見デー). During these events, families and train enthusiasts can get close to various rolling stock, including the Doctor Yellow, and explore maintenance vehicles, equipment, and even go inside some train cars. These occasions often feature educational booths, child-friendly experiences like driving simulators, and local food stalls, making it a popular family outing.

For casual visitors or photographers hoping to glimpse the depot’s activity without attending an official event, several vantage points are available near the Yashio (八潮) residential area and along nearby overpasses and pedestrian bridges. The Yashio Higashi Park (八潮東公園) area and roads running alongside the depot offer clear lines of sight into the yard. While not guaranteed, early mornings or weekends sometimes provide views of trains being moved in or out of service.

Photographing the Doctor Yellow or Shinkansen at Ōi Depot requires patience and timing. The most successful photographers recommend using telephoto lenses and scouting locations ahead of time. As tripods can obstruct narrow sidewalks and attract attention, it’s better to use compact setups. Golden hour lighting around sunset creates a warm glow on the silver body of the trains, adding a cinematic touch to images. Some railfans prefer twilight, when interior maintenance lights create dramatic contrasts against the steel tracks.