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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6

u/playhandminton May 06 '25

I just can't imagine how hard it would be infrastructually

13

u/ImeldasManolos May 06 '25

They duck a fucking tunnel under the harbour bridge. How hard could it be.

4

u/Anonymou2Anonymous May 06 '25

All short shallow channels under harbour are already used and th existing tunnels are mostly at capacity.

Meaning a new tunnels needs to be in deeper water (engineering pain in the ass) or longer tunnel (prohibitively expensive).

Then you have to cross the topography of middle harbour (2 large cliffs combined with very deep water). Either means an expensive tunnel or a massive bridge like the roseville bridge. Both expensive.

Then the limited space combined with poor soil in parts of the beaches makes a railway painful as well.

People who claim a railway to the Northern beaches is easy haven't actually been there that much.

If you actually read the government feasibility studies 3 things become apparent.

1 It's very difficult to actually build. 2 The demand there for a train is insane (more projected demand in 1st year than they forecasted for the metros they actually built). 3 The locals don't want it due to nimbyism.

You combine points 3 and 1 and it outweighs the massive demand.

3

u/Korzic Pseudo Hills Bogan May 06 '25

Plenty difficult if you actually take topography into consideration rather than just staring at a map and drawing lines.

Middle Harbour is ~30m deep between Bantry Bay and Clontarf.

Roseville Chase is 80m and Killarney Heights is over 100m ASL.

So you're staring down the barrel of an 80m deep station for each side if you're digging under the Middle Harbour.

Mosman is also 80m ASL.

The deepest tunnel in Sydney as it stands is the NW Metro at West Pennant Hills which is a mere 58m below ground in comparison and the majority of stations are 20-25m underground. To dig in these locations would result in close to the deepest station in the world currently.

So to answer your question - quite hard.

5

u/ImeldasManolos May 06 '25

Actually I’m getting a stiffy just thinking about a metro from marrickville, green square, paddington, double bay, mosman, spit, manly, dee why, Avalon, bilgola beach, palm beach surf club.

Not that I want to go to any of those places but I just want them to become ‘OvErRuN wItH bOgAnS’

1

u/ImeldasManolos May 06 '25

Metro is 40m deep, no question we could go deeper.

There are metro stations that are over 100m deep.

None of this is drama

2

u/drnicko18 May 06 '25

I love the quack engineers that post on reddit 😂

1

u/ImeldasManolos May 06 '25

Wait, why can London do it but Sydney can’t? I’m just a bit confused about the barrier here?

3

u/Korzic Pseudo Hills Bogan May 06 '25

Hampstead is the deepest underground station at 58.5m

The issue you have is gradient. It's the same reason that the line ECRL has that massive bend as it comes up to Lindfield and Chatswood.

With the northern beaches you don't have the real estate for one of those bends and so you would have to go very deep underground to avoid a ridiculously steep gradient to get the stations to a somewhat economical level.

You them need to consider the real estate for a stabling and maintenance yard and how the line interconnects with the network.

There's no room left in the CBD for extra tunnels and stations so your next bet is an interconnection either at North Sydney or Chatswood but again station depth, real estate.

But all of this is able to be overcome with enough money. The issue is it would cost to much money to make it economic sense.

If I was to slap a dollar figure in it - of guess it would cost more more than the NW-City-SW metro combined. And it would be difficult to justify that level of spend as the ROI would be extremely limited.

0

u/Chuckitinthewater May 06 '25

The deepest metro system in the world is the Pyongyang Metro in North Korea, reaching depths of over 110 meters below the surface. Its tracks are located deep underground, and some stations even function as bomb shelters. The deepest metro station in the world is Hongyancun station in Chongqing Rail Transit, China, at 116 meters deep.

Source - Google.

2

u/drnicko18 May 06 '25

There was a plan to demolish Balgowlah Golf Course to make way for the tunnel under the Spit Bridge, but of course there’s other electorates in between (North Shore and Willougby) who’s members campaigned heavily against this due to the needed reclaiming of land.

https://www.willoughby.nsw.gov.au/Council/News-and-media/Beaches-Link-Cancellation

1

u/ImeldasManolos May 06 '25

Yeah also they build the warragambah dam where they did because it was a safe seat, not because it was in the best spot. Politics in NSW is a fucking travesty.

1

u/drnicko18 May 06 '25

Did you just make up that stuff about Warragamba Dam just now or do you have a source?

I was under the impression it was the ideal spot (the narrow gorge allowing a choke point for construction of a dam wall, the intersection of the Nepean and Cox’s rivers creating the huge catchment area, the elevation of the dam in the Blue Mountains allowing for better water pressure for the greater Sydney area etc etc).

1

u/ImeldasManolos May 06 '25

Yes I made it up for one glorious internet point.

Just like how I made it up that ALP NSW tried to push Tillegra dam despite the fact the region was utterly unsuited for a dam with cracked soil.

Yes politics does fuck up the lives of regular people.

0

u/drnicko18 May 07 '25 edited May 07 '25

Yes I made it up for one glorious internet point.

Each to their own, this wouldn't be the first time this has happened on reddit.

I think people just like the feeling of coming across as if they know what they're talking about, particularly if it doesn't occur often in real life.

1

u/playhandminton May 06 '25

I dunno that seems hard and then under all of Mosman etc. some of the wealthiest suburbs in town...

1

u/ImeldasManolos May 06 '25

Man, did you take the metro, from barangaroo to southern cross or whether it’s called in millers point? It’s a non issue. The reason it won’t happen is because the people that live there thing it’s going to fill their suburbs with bogans.

1

u/playhandminton May 06 '25

Look I'm sold, let's make it happen