As I mentioned before, Yotsuya, located in central Tokyo, is a complicated station shared by the JR East Chuo Line and the Tokyo Metro Marunouchi Line. For example, JR East’s Yotsuya Station is situated in a valley, with a railway tunnel located just beside it. On the other hand, although the Tokyo Metro Marunouchi Line is a “subway,” its Yotsuya Station is on an elevated track rather than underground. It’s quite confusing—so how are these two stations positioned relative to each other?
I recently captured a photo that clearly explains the mystery. In the top image, you can see a Tokyo Metro Series 2000 EMU on the left and a JR East Series E231 EMU on the right. Notice how the 2000 series rides above the E231 series—literally placing the “subway” above the JR East Line. This curious structure has a fascinating backstory.
The history begins in 1894, when the Kobu Railway (now JR East) built Yotsuya Station in the bottom of a valley. Over half a century later, in the 1950s, Eidan (now Tokyo Metro) began planning the Marunouchi Line as part of Tokyo’s growing subway network. They faced a major challenge: the line was too deep to tunnel beneath the Chuo Line. The solution was unexpected—the Marunouchi Line would be built as an elevated track directly above the Chuo Line, creating this unusual vertical layout.
Today, Yotsuya Station remains a rare example of Tokyo’s intricate railway history—a place where “subway” really means above rather than below.
To close, here’s one more photo showing the Marunouchi Line track as it emerges from a tunnel and approaches its elevated Yotsuya Station. This is a unique feature in Tokyo—a singularity in a city of wonders.
