MTR in section

Hong Kong1979–2022A railway in layers

The MTR, in section

Hong Kong's metro was not built all at once. Each new line arrived in a city that already had railways, foundations and a harbour in the way, and had to pass over, under or around them.

Admiralty shows how. Its first two lines were planned together and share two levels. The two newest were dug in beneath them more than thirty years later, while trains kept running overhead.

Watch the film 4 min Explore the network
Section through Admiralty station A simplified vertical section through the ground at Admiralty, showing the platforms of four railway lines at four depths below the street.
Fig. 1Admiralty station in simplified section, based on MTR's station layout drawing. The levels are in the right order but not to scale, and the ground layers are typical of reclaimed harbour-front land rather than a survey of this site: from the top, reclaimed fill, marine deposits, weathered rock and rock. mPD is height relative to Hong Kong's survey datum, close to sea level. [D01, D03, D10, C11]
  1. 1980Tsuen Wan LineLevels 2 and 3
  2. 1985Island LineSame levels, across the platform
  3. 2016South Island LineLevel 6 · −33.6 mPD
  4. 2022East Rail LineLevel 5
Sheet01

The film How the layers were laid down

A short animated film, from the first dig under Nathan Road in 1975 to the fourth railway tunnel under the harbour in 2022. It has no sound; the captions tell the story.

Length
About 4 minutes
Keys
Click the picture or press K to play or pause; Space works on the play button and scrubber. ← → skip 5 seconds.
1970s

Loading…

0:00 / 4:00

    Read the film as text
    Sheet02

    The network by year, and by level

    Drag the year to see the network grow. Switch to Level to colour every station by how it was built: on a viaduct, at ground level, or underground. Select a station for its details.

    Drawing
    Schematic map. Distances and angles are simplified.
    Covers
    The ten heavy-rail lines. Light Rail and the high-speed line are left out.
    2026

    Arrow keys move one year at a time. The station counts below update as the year changes.

    98
    Stations open
    46
    Underground
    27
    Elevated
    21
    At ground level
    4
    Mixed levels
    Colour by

    Scroll or swipe inside the map to see all of it.

    Schematic map of the MTR heavy-rail network

      Select a station on the map, or choose one from the list.

      Lines are drawn in today's colours, also for years when they ran under another name. East Rail and the Tuen Ma Line's predecessors were built by the KCR and joined the MTR in 2007.

      Sheet03

      In three dimensions every line at its own level

      The network in its real geography, with each line at its own level and depth stretched so the levels show. Turn it, tilt it below sea level, zoom in on an interchange, and follow the tubes under the harbour. Select a station to see how deep each line runs there.

      Heights
      Relative to sea level, stretched by the slider. Streets on the flat harbour-front land are about 5 m above it.
      Markers
      Solid: a source gives the level, or it is at street level. Open: not published, so estimated. Squares: hillside entrances.
      ×60

      Building the model…

      Highlight lines

        Drag to turn · Shift-drag or right-drag to move · Pinch or Ctrl/⌘-scroll to zoom · With the model selected: arrows turn, Shift + arrows move, + and − zoom, 0 resets, Esc clears a station.Drag sideways to turn · Pinch to zoom · Use the buttons on the model to tilt. Tunnel dips and bridge heights are approximate.

        Sheet04

        Interchanges where the layers meet

        Where lines cross, their platforms have to be stacked. Some were planned together, so passengers change trains by walking across the platform. Others were added decades apart, and the new platforms had to fit around the old ones.

        Drawing
        Vertical stacks, simplified. Levels are in order but not to scale.
        Sheet05

        How they built it six ways to make room for a railway

        The level a line runs at depends a lot on how it was built. Building in a trench from the surface keeps a line shallow. Going through rock lets it go deep. Viaducts and bridges carry it above everything.

        Drawing
        Diagrams show the principle, not a particular site.
          Sheet06

          Sources and notes

          Dates come from MTR Corporation and KCRC reports and government papers. Depths are harder to pin down: where no primary source gives a figure, the page says so.