Super Bell Subway is a course from Mario Kart 8 and Mario Kart 8 Deluxe in the 2nd set of downloadable content. It is the third course in the Bell Cup. The course is located in the Golden Bell, a subway station, and the surrounding tracks.
The courses starts in the station with a U-Turn going to the left that leads into a large area with stairs leading into the subways. The subway portion of the track has trains running through it. Players can get on top of the trains via raised platforms that are accessed through the side of the course At the end of the subway, the train track splits and has stairs that lead up back into the large area of the station with another set of stairs taking the players to last bend before the finish. After the U-Turn is a straightaway to the finish line.
This track only plays a half of the music when racing on the course, and the other half plays only when watching a highlight reel.
The map that is at the starting line of the track appears to connect nearly all of the raceways that appear in Mario Kart 8. Several other detailed maps by the subway lines also include the names of playable courses and the in game business advertisements. Much like an actual subway, there are exits for different stations written on signs above the track stating the names of various courses.
In the subway, there is a reference to World 1-2 as graffiti on the wall.
Like Sunshine Airport, this track features a P.A. voice in the background that can be heard faintly. The female intercom speaks German, including several grammar errors however, and says general things heard in a German train station.
This is one of three nitro courses in Mario Kart 8 without anti-gravity sections, the other two being Excitebike Arena and Animal Crossing, and the only one that's not a crossover course.
It is revealed in a "Local information" map that the subway system is underground what seems to be the same town N64 Rainbow Road hovers over.
The map has a key showing the location of several companies mentioned throughout the game (like "Bowser Oil" or "Yoshi's Egg Market"), but "Morton Construction" is listed with a typo as "Moton Construction".