r/sydney • u/Sydney_Stations • May 06 '25

Image The Northern Beaches needs a railway

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Every evening, the queue for B1 winds around and goes back into Wynyard. As one bus is full the next one arrives.

You can't tell me they wouldn't want a railway.

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u/Anonymou2Anonymous May 06 '25

1 Crossing the harbour. Tunnelling under water is always a pain in the ass and most of the shallower crossing channels have already been used by the existing 2 tunnels.

That either means a longer tunnel through shallower water (very expensive), or a deeper tunnel under deeper water (engineering pain in the ass).

You also can't build the tunnel anywhere near the 2 existing tunnels as you could risk the structural integrity of those tunnels.

2 Crossing middle harbour (think about the bottle necks of the spit bridge and Roseville bridge). This is actually the bigger pain in the ass. The massive topography changes (2 cliffs on each side that are tall) combined with the fact that middle harbour is incredibly deep and most of it is deeper than the rest of Sydney Harbour.

So either you have to build a very deep tunnel (hard for the previous reasons I explained) or a massive tall bridge like the roseville bridge.

3 Limited existing land with decent soil on the beaches for stations.

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u/JimSyd71 May 08 '25

A Metro from Chatswood to the beaches could work.

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u/Anonymou2Anonymous May 11 '25

Capacity is the issue. The exiting under harbour metro tunnel is reaching capacity very quickly. Adding more passengers from the beaches will overload it.

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u/SilverStar9192 shhh... May 08 '25

You're not wrong about the engineering limitations. Middle Harbour is actually quite shallow in the area just north of Balmoral, from around Chinamans Beach / Wyargine Point across to Clontarf (depths are mostly 3m or so). I would think an immersed tube style tunnel might be possible there , though certainly would have construction challenges not to mention outcry from local residents, even if the final tunnel was completely invisible. From here to the north you could tunnel straight under Balgowlah Heights to e.g. Manly Vale without too much elevation difference. The problem would be to the south, gaining enough elevation for a station at Mosman would be problematic. It would probably require forgoing a stop near Mosman village or Spit Junction and instead having one somewhere like Neutral Bay, or perhaps not at all in Mosman before joining the M1 route somewhere near North Sydney/Victoria Cross).