First cab off the rank of the line-by-line photo essays: the Island Line. You can see the whole set of photos here, and a track diagram is here. The vast majority of the line is in deep level bored tunnels, not cut and cover like the rest of the original MTR network, giving the line a distinctive look at platform level.
Sheung Wan is the western terminus, and is a deep level station resulting the the tubular tunnels for the platforms. Beyond the platforms there is a dead end turnback siding, trains drop off passengers at one platform:
Then after changing ends in the tunnel, pick up passengers on the other platform, along with a new driver for the eastbound trip:
Sheung Wan was also interesting in that it has a pair of “ghost platforms” at one exit, built to provide for future expansion – the best explanation of the situation is on this website (via Google Translate). Unfortunately when I visited they had been blocked off, with the construction of the West Island Line instead, the area will be used for more escalators.
The next two stations are Central and Admiralty: they provide a cross platform interchange with the Tsuen Wan line.
Beyond here the line is back in deep level tunnels, with the stations all looking the same except for their wall colours.
North Point station is still deep underground, but has an cross platform interchange with the Tseung Kwan O line.
The next station, Quarry Bay, also has an interchange with the Tseung Kwan O line but the two lines are a long way apart, requiring two escalators and a lot of walking.
After a few more stops, the line reaches ground level at Heng Fa Chuen station. Here the platforms are either side of the running lines, with a row of columns holding up the concourse on top.
Heng Fa Chuen is one of the few above ground stations on the ‘original’ part of the MTR, and was not retrofitted with full height platform screen doors in the 2000s. Instead half height automatic platform gates will be installed, with the first part of the installation under test during my visit.
Continuing east, the track climbs onto a viaduct and passes the Chai Wan Depot, which maintains both the track and trains of the Island Line. Like all MTR rail depots, a podium has been built over the top of the car sheds to allow housing to be built.
Just beyond the depot is Chai Wan statiom, the eastern terminus of the line. With an island platform between the tracks, there is enough time off-peak for a train driver to change ends then take the same train out again.
To allow trains to enter the station at line speed, overrun tracks exist beyond the platforms.
(none of this 30 km/h crap you see in Melbourne!)
The overrun tracks are still on a viaduct, with a building straddling the tracks, and a beefy set of buffers located before the actual end of the track.
From here the only thing left to do is catch the train back – you could step off at Shau Kei Wan and change to the tram…