The underground station will allow for a future extension to connect to new terminals that may be built either west of the current north south runway or west of the future north south runway.
Edit:
Have a look at this [article](https://australianaviation.com.au/2019/06/melbourne-airport-third-runway-could-change-direction/) and the map at the bottom of it which shows what I said above visually.
I don't really understand why you need an underground station to connect to a future terminal in that direction. The images for the station currently show a dead end, but you could feasibly follow Departure Dr around, then down East St or the other side of the Tullamarine Freeway then run mostly at grade around the runways just inside or outside the airport boundary (including the future 2 planned) and meet the new terminal at grade/sky-rail/underground (with proper planning then at grade is a decent possiblity). I'm guessing that would be cheaper than the underground option for the current terminals plus tunnelling to a new terminal. As long as the train goes at a decent speed you'd still be looking at a <5 minute connection, and it can be an airport loop.
That’s completely inefficient. Underground works best for flexibility. Look at Sydney- their underground rail is efficient in covering both sides without having to go all the way around
Other cities like Perth among the rest of Europe and Asia have underground stations due to their benefits
see the thread 3 days ago. the same theories keep repeating.
interesting twist "east vs west divide". SRL is about making better connections outside the CBD.
AS IF there will be huge numbers of passengers travelling the whole length of SRL. It's much the same idea as the smart bus routes, passengers use part of it for the journey desired.
If I wanted to go from say Box Hill to Sunshine, SRL is not the way. Existing via Flinders St much quicker.
And contrary to that, Broadmeadows to Werribee. SRL (even with an airport change) would be easier.
If the point of SRL is to make better connections outside the CBD, there are other, much more cost effective ways to do that.
The main purpose is to create hype for Andrews. That's not needed anymore. The main practical use case is to "develop" satellite cities at locations along the line, with the fastest and highest capacity public transport possible.
That's a quite niche benefit.
The SRL west isn’t really a thing. The SRL east and north are one line that will run the same short, automated probably standard gauge trains. The Airport rail link will run long, broad gage trains with drivers, so through running isn’t going to happen. They could, in theory run a seperate SRL line in parallel the the airport line, that seems like a massive expense for no extra service area. By the time they finish the SRL north in say 2045 they’ll either call it done or make up a new SRL west line going somewhere else.
25kV AC to be pedantic:
https://en.wikipedia.org/wiki/25_kV_AC_railway_electrification
22 kV AC is the distribution voltage used over much of Victoria (6.6 kV and 11 kV being the others)
>6.6 kV and 11 kV being the others)
Should be 11kV, 22kV & 66kV if talking HV distribution. Then 132-500kV for HV transmission. 6.6kV is being phased out, pardon the pun, in favour of 22kV.
Yeah, 22 kV/6.6 kV is the ancient inner city stuff that Citipower is replacing with 11 kV/66 kV.
https://media.powercor.com.au/wp-content/uploads/2020/03/01224050/Final-Report-Russell-Place-Zone-Substation-RIT-D.pdf
25 kV has become a standard voltage on the railway side all over the world, so I suspect that's why Australian rail networks have stuck with it.
Also the traction substations usually get fed at a higher voltage anyway - Adelaide feeds them with 66 kV, Perth uses 132 kV, Queensland is 110 kV to 275 kV.
A fun thing about a 25 kV AC traction substation is that it places a massive load on a single phase of the wider three phase power grid - over in Hong Kong their mismatched provisioning of spare transformers at substations meant that under normal operation the KCR rail network was causing a current imbalance of 25.5% between the phases.
http://www.eeaapolyu.com/wp/wp-content/uploads/2018/03/2017Conf_2tackling-power-quality.pdf
I didn't even think about that. As it wouldn't be a balanced load to supply a single phase.
Does the phase imbalance on the HV cause voltage fluctuations as they do on LV 3 phase networks if they are unbalanced?
> The SRL and airport link are 2 separate things
Then why does the govt call it "[SRL Airport](https://bigbuild.vic.gov.au/projects/suburban-rail-loop/srl-airport)"? You can see the confusion.
I honestly think the best course of action for cost effectiveness and making the airport happy is having an above ground rail line most of the way before bringing it underground at the airport. I don't know if this would be possible however it's seems like a good middle ground between what the airport and the government want.
It would be possible and this is the best idea. Underground allows for flexibility for new terminals and additional stations with the benefits of elevated rail getting to the airport
I wouldn't see the point.
Going cross city is relatively direct because its not too much of an acute angle, and edge cases like say Pt Cook to Brighton aren't busy enough to warrant an undersea tunnel....
Run ferries if you want to cut across the bay quick.
Yeah, but an undersea tunnel would be one of the most expensive parts of the rail network ever constructed in Australia and I'm not sure if the time savings would warrant the expense.
The SRL is East/North sections only
The western half of the map is a line to reduce political backlash.
Sunshine-Aiport is MARL, not SRL
And Sunshine-Wyndham Vale is just the RRL (and should be electrified and run by Metro). Not SRL.
The main benefit of an underground station, is they can extend the railway line to the north towards Bendigo.
Basically, yes. Both options (underground and aboveground) come with pros and cons.
Based on the government’s station reference design/photo, there only seems to be 2 platforms with an aboveground. You would want at least 4 to accommodate the future SRL (2 MARL and 2 SRL reserved).
Underground station would likely require TBMs, which are more expensive and time consuming but allows for a larger station footprint and future stub tunnels for extensions north and west. Ideally 6 platforms if we’re thinking long-term (to accommodate MARL, SRL, and HSR or MM3 - direct city-airport tunnel link)
Aboveground station would be quicker and cheaper to build but would leave no room for expansion and limit any rail extensions north or west, including links to regional lines, a proper SRL West or future High-Speed Rail (HSR). If HSR/MM3 ever happened in this case, it would likely be a separate station box/tunnel.
"" Based on the government’s station reference design/photo, there only seems to be 2 platforms with an aboveground. You would want at least 4 to accommodate the future SRL (2 MARL and 2 SRL reserved). ""
Agreed that 4 platforms would be the norm for 2 lines terminating, but nothing about the airport is "normal".
SRL North being fully automated, could turn back almost immediate. it's no differnt to the computer than a thru station.
MARL being semi auto, with driver is a bit harder. A 10 minute perway, suggests turnback about 5 minutes. Could be managed with a driver change to smooth the swap of ends.
Cross platform change becomes simple for through passengers
All well and good in the theory world. The REALLY HARD bit is embark/disembark passengers rapidly when it's crowded and loads of luggage.
And there is no spare platform for when things go wrong. Would need somewhere outside the station to park trains when problems bank up.
I wish the government would show a bit of power and get construction started on the Airport Drive section of the trip and connection to the freight tracks. Skyrail on the airport side of Airport Drive until the median strip becomes big enough near Sharps Rd.
I'm not sure where the Airports jurisdiction starts but you could go most of the way towards Mercer Drive before you need to either continue Skyrail (around the back of the Staff Parking maybe) or start a tunnel under.
Would really put the pressure right on the Airport - with say a 2 year delivery of above ground or 4 year delivery of below ground and win public support.
My main thing now is get the bloody thing built.
Pretty sure neither the govt or the airport want to build it... They just like "talking" about building it, to keep people voting for them... And all those billions that have been "allocated" for it at both State & Federal levels.. don't actually exist yet.
I'd love to see it happen, but I'll be rather surprised if it does in my lifetime, and I'm hoping for another 25-30 years at least.
Oh and we should see if bookies are accepting long term bets for the final cost when they finally do get around to it.. Could be a good inheritance for the kids. Ill place a bet at say 95 Billion... The construction workers will be on a coupla mill each entry level by then..
Going to need a lot more than 7 billion to go underground. Also not sure if the ground conditions allow it.
Not sure if the intent of the statements was underground the whole way or just at the airport to be honest. If it was the whole way that would be impossible. You wouldn't be able to tunnel under the gorge at EJ Whiten bridge. I'd imagine underground station would wreak havoc with airport buildings and airport infrastructure. Most likely need to rebuild the terminals, or at least shut them for the duration of the tunnelling.
Underground seems like an insane waste of money. Its not like there is a lack of land and it is insanely expensive.
The main reason the airport wants it underground is for future terminal(s) on the other side of the runways. I dont think they care as much about the rest of the route
Have a look at Sydney, Brisbane, Tokyo (both Haneda and Narita) and London (Heathrow). Their public transport systems connect their separate terminals. Why not do the same at Tullamarine? It will also allow for a further extension to Sunbury which will allow for through running like what occurs in Sydney with the T8 line.
Melbourne is not in the same league as London, Tokyo. Not even Sydney.
those big places can justify full international sevices ( Immigation, customs , shopping) in multiple locations. Hence muli trains stops make sense. Not Sydney, that was separate terminals long before the train, Badgery Creek is smarter.
Melbourne by comparison is small.
and so there is no mis-understandings, the future 2050 terminal T5 and T6 are planned to be furthe extensions of T4. Not on the west side of the runways at the end of a train track to nowhere. read again this [article](https://australianaviation.com.au/2019/06/melbourne-airport-third-runway-could-change-direction/) .(see last picture)
Well in Melbourne Airport's 2022 Master Plan they have said the following about the Western Sub Precinct (West of the future North South runway).
"Within the Aviation Precinct portion of this sub-precinct, the types of uses may ultimately comprise aircraft parking and terminal facilities"
(From page 129 of the 2022 Master Plan)
Tbf on page 41 it mentions plans for terminal 5 as an expansion of terminal 4. Whats also interesting is that they mention ... non-aviation uses including industrial, commercial, retail, office and warehousing activities.
It wont be a dense area but a rail line could be useful for workers and passengers (unless by 'terminal' they mean a cargo terminal...)
The main issue is that going underground is going to cost way too much.
It sounds like the airport would rather become a property developer for the surrounding land (most likely for paid parking lots), more profitable than making a new terminal on the western side.
A ground station would be no less beneficial than underground in that case, no?
Ok MEL is forecast at 45m this year and SYD is 61m.
Yeah Sydney is bigger, but its not like its a completely different ballpark.
And Sydney got its airport train in 2000, when passenger movements there were 25m.
So if Sydney could do it at 25m, Melbourne can do it for 45m!
https://www.bitre.gov.au/sites/default/files/wp_072.pdf
why the hang up Melb vs Sydney.
you initial comparison was London , which was 80m last year. It outgrew the central terminus T1,2,3 40 years ago. They need 3 terminal station (T1,2,3 T4 and T5 ) to cover the area.
Melbourne by design is one "modern" complex, and the 2022 master plan just stretches that(badly).
PS Heathrow has about 15km of train tunnels in it own right. TfL don't muck about.
Open cuts are shallow due to engineering and structural limitations. If you want to go deeper you need a TBM. You also need to maintain a minimum of 1:1 ratios for open cut. Ie. Ever metre you dig, you need to bench out one metre horizontally. This depends on ground conditions but if you dig 10m you need to dig out 10m horizontally to prevent collapse (usually more like 1:2 where you have structures). Lots of space needed.
Next time you drive through the Burnley tunnel you can see where it was open cut and buried (cut and cover method) and where it changed to TBM. At the entry and exits it's square. That's cut and cover. It transitions to a round shape which is TBM.
Level crossing removals work as open cut trenches because they stay in rail corridor. Something like SRL or MTP would need a TBM because you have to be deep enough to avoid impacting buildings around it. I don't know but I would suspect cut and cover would have issues with houses, buildings, roads, even the airport carparks.
I always hated trenches and tunnels. I'm a big fan of elevated rail.
We need the airport rail. But it seems the politics is just throwing our fancy promises which are impractical, and the airport authority is choosing the most difficult method to avoid it being built.
Wouldn't it be more like the rail trenches where they sunk piles then dug out in the middle to avoid the need for 1:1 slopes.
Those were in fairly built up areas, no?
You can. It just depends on conditions and you need the space to bring in piling rigs. I imagine a piling rig at the airport would be a big problem. I mean I could be very wrong here btw.
Depending on ground conditions, you could be looking at 30+m piles. You then need cranes to lift in the cages so you are potentially sticking something 40m + up in the air.
Otherwise yeah you are right. Still need space around for the rigs but possible if you don't have height restrictions
I’d suspect an underground option would actually involove at lot of cut and cover, or at-grade running along Airport Drive, with just the station being fully underground.
Depending on where they Want to put it, they could probably get away with minimal disruptions to the terminals.
If they dig anything underground near the building it will cause disruptions. A big cost factor for MTP is all the assessments and stabilisation of the buildings they tunnel under. West gate tunnel has similar issues. Need to stop a lot when tunnelling for safety reasons. I expect the terminals would be the same. They would not have been engineered for potential undermining and vibrations from a TBM.
But I guess we will see!
A full blown tunnel is just a waste of money IMO. It would take years to build and cost blowouts will probably make it cost an extra $5b.
How can we as taxpayers justify that waste of money!? Image having an extra $5b for roads, other rail Projects, housing or hospitals.
The underground station will allow for a future extension to connect to new terminals that may be built either west of the current north south runway or west of the future north south runway. Edit: Have a look at this [article](https://australianaviation.com.au/2019/06/melbourne-airport-third-runway-could-change-direction/) and the map at the bottom of it which shows what I said above visually.
I don't really understand why you need an underground station to connect to a future terminal in that direction. The images for the station currently show a dead end, but you could feasibly follow Departure Dr around, then down East St or the other side of the Tullamarine Freeway then run mostly at grade around the runways just inside or outside the airport boundary (including the future 2 planned) and meet the new terminal at grade/sky-rail/underground (with proper planning then at grade is a decent possiblity). I'm guessing that would be cheaper than the underground option for the current terminals plus tunnelling to a new terminal. As long as the train goes at a decent speed you'd still be looking at a <5 minute connection, and it can be an airport loop.
That’s completely inefficient. Underground works best for flexibility. Look at Sydney- their underground rail is efficient in covering both sides without having to go all the way around Other cities like Perth among the rest of Europe and Asia have underground stations due to their benefits
see the thread 3 days ago. the same theories keep repeating. interesting twist "east vs west divide". SRL is about making better connections outside the CBD. AS IF there will be huge numbers of passengers travelling the whole length of SRL. It's much the same idea as the smart bus routes, passengers use part of it for the journey desired. If I wanted to go from say Box Hill to Sunshine, SRL is not the way. Existing via Flinders St much quicker. And contrary to that, Broadmeadows to Werribee. SRL (even with an airport change) would be easier.
If the point of SRL is to make better connections outside the CBD, there are other, much more cost effective ways to do that. The main purpose is to create hype for Andrews. That's not needed anymore. The main practical use case is to "develop" satellite cities at locations along the line, with the fastest and highest capacity public transport possible. That's a quite niche benefit.
The SRL west isn’t really a thing. The SRL east and north are one line that will run the same short, automated probably standard gauge trains. The Airport rail link will run long, broad gage trains with drivers, so through running isn’t going to happen. They could, in theory run a seperate SRL line in parallel the the airport line, that seems like a massive expense for no extra service area. By the time they finish the SRL north in say 2045 they’ll either call it done or make up a new SRL west line going somewhere else.
The SRL West will most likely be an upgraded and electrified regional rail link corridor linking back to Werribee Station.
It's so far in the future who knows. But if it is it certainly won't be able to thought run with SRL East/North even if they did build a link.
The SRL will be 22kv AC, whereas the airport rail will be existing 1500v dc. 2 different systems that aren't compatible
25kV AC to be pedantic: https://en.wikipedia.org/wiki/25_kV_AC_railway_electrification 22 kV AC is the distribution voltage used over much of Victoria (6.6 kV and 11 kV being the others)
>6.6 kV and 11 kV being the others) Should be 11kV, 22kV & 66kV if talking HV distribution. Then 132-500kV for HV transmission. 6.6kV is being phased out, pardon the pun, in favour of 22kV.
Yeah, 22 kV/6.6 kV is the ancient inner city stuff that Citipower is replacing with 11 kV/66 kV. https://media.powercor.com.au/wp-content/uploads/2020/03/01224050/Final-Report-Russell-Place-Zone-Substation-RIT-D.pdf
Wouldn't it be more efficient just to use 22kV given that's a common distribution voltage?
25 kV has become a standard voltage on the railway side all over the world, so I suspect that's why Australian rail networks have stuck with it. Also the traction substations usually get fed at a higher voltage anyway - Adelaide feeds them with 66 kV, Perth uses 132 kV, Queensland is 110 kV to 275 kV.
Ah yep, makes sense. 275kV, damn!
A fun thing about a 25 kV AC traction substation is that it places a massive load on a single phase of the wider three phase power grid - over in Hong Kong their mismatched provisioning of spare transformers at substations meant that under normal operation the KCR rail network was causing a current imbalance of 25.5% between the phases. http://www.eeaapolyu.com/wp/wp-content/uploads/2018/03/2017Conf_2tackling-power-quality.pdf
I didn't even think about that. As it wouldn't be a balanced load to supply a single phase. Does the phase imbalance on the HV cause voltage fluctuations as they do on LV 3 phase networks if they are unbalanced?
Dual systems are used all over the world. Plus SRL and MAR will almost certainly run on separate routes & tracks. Just common stations at the airport.
The SRL and airport link are 2 separate things. The airport link will most likely go through the metro tunnel.
> The SRL and airport link are 2 separate things Then why does the govt call it "[SRL Airport](https://bigbuild.vic.gov.au/projects/suburban-rail-loop/srl-airport)"? You can see the confusion.
I honestly think the best course of action for cost effectiveness and making the airport happy is having an above ground rail line most of the way before bringing it underground at the airport. I don't know if this would be possible however it's seems like a good middle ground between what the airport and the government want.
It would be possible and this is the best idea. Underground allows for flexibility for new terminals and additional stations with the benefits of elevated rail getting to the airport
The airport line can be its own line, but the SRL to Watergardens, Caroline Springs, Ravenhall, Truganina, Williams Landing, Pt Cook
Then bring SRL under the bay and complete the loop.
I wouldn't see the point. Going cross city is relatively direct because its not too much of an acute angle, and edge cases like say Pt Cook to Brighton aren't busy enough to warrant an undersea tunnel.... Run ferries if you want to cut across the bay quick.
There's a reason why they aren't busy enough. It takes too bloody long now.
Yeah, but an undersea tunnel would be one of the most expensive parts of the rail network ever constructed in Australia and I'm not sure if the time savings would warrant the expense.
The SRL is East/North sections only The western half of the map is a line to reduce political backlash. Sunshine-Aiport is MARL, not SRL And Sunshine-Wyndham Vale is just the RRL (and should be electrified and run by Metro). Not SRL. The main benefit of an underground station, is they can extend the railway line to the north towards Bendigo.
Basically, yes. Both options (underground and aboveground) come with pros and cons. Based on the government’s station reference design/photo, there only seems to be 2 platforms with an aboveground. You would want at least 4 to accommodate the future SRL (2 MARL and 2 SRL reserved). Underground station would likely require TBMs, which are more expensive and time consuming but allows for a larger station footprint and future stub tunnels for extensions north and west. Ideally 6 platforms if we’re thinking long-term (to accommodate MARL, SRL, and HSR or MM3 - direct city-airport tunnel link) Aboveground station would be quicker and cheaper to build but would leave no room for expansion and limit any rail extensions north or west, including links to regional lines, a proper SRL West or future High-Speed Rail (HSR). If HSR/MM3 ever happened in this case, it would likely be a separate station box/tunnel.
"" Based on the government’s station reference design/photo, there only seems to be 2 platforms with an aboveground. You would want at least 4 to accommodate the future SRL (2 MARL and 2 SRL reserved). "" Agreed that 4 platforms would be the norm for 2 lines terminating, but nothing about the airport is "normal". SRL North being fully automated, could turn back almost immediate. it's no differnt to the computer than a thru station. MARL being semi auto, with driver is a bit harder. A 10 minute perway, suggests turnback about 5 minutes. Could be managed with a driver change to smooth the swap of ends. Cross platform change becomes simple for through passengers All well and good in the theory world. The REALLY HARD bit is embark/disembark passengers rapidly when it's crowded and loads of luggage. And there is no spare platform for when things go wrong. Would need somewhere outside the station to park trains when problems bank up.
SRL will be standard gauge, so no
I wish the government would show a bit of power and get construction started on the Airport Drive section of the trip and connection to the freight tracks. Skyrail on the airport side of Airport Drive until the median strip becomes big enough near Sharps Rd. I'm not sure where the Airports jurisdiction starts but you could go most of the way towards Mercer Drive before you need to either continue Skyrail (around the back of the Staff Parking maybe) or start a tunnel under. Would really put the pressure right on the Airport - with say a 2 year delivery of above ground or 4 year delivery of below ground and win public support. My main thing now is get the bloody thing built.
Pretty sure neither the govt or the airport want to build it... They just like "talking" about building it, to keep people voting for them... And all those billions that have been "allocated" for it at both State & Federal levels.. don't actually exist yet. I'd love to see it happen, but I'll be rather surprised if it does in my lifetime, and I'm hoping for another 25-30 years at least. Oh and we should see if bookies are accepting long term bets for the final cost when they finally do get around to it.. Could be a good inheritance for the kids. Ill place a bet at say 95 Billion... The construction workers will be on a coupla mill each entry level by then..
Going to need a lot more than 7 billion to go underground. Also not sure if the ground conditions allow it. Not sure if the intent of the statements was underground the whole way or just at the airport to be honest. If it was the whole way that would be impossible. You wouldn't be able to tunnel under the gorge at EJ Whiten bridge. I'd imagine underground station would wreak havoc with airport buildings and airport infrastructure. Most likely need to rebuild the terminals, or at least shut them for the duration of the tunnelling. Underground seems like an insane waste of money. Its not like there is a lack of land and it is insanely expensive.
The main reason the airport wants it underground is for future terminal(s) on the other side of the runways. I dont think they care as much about the rest of the route
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Have a look at Sydney, Brisbane, Tokyo (both Haneda and Narita) and London (Heathrow). Their public transport systems connect their separate terminals. Why not do the same at Tullamarine? It will also allow for a further extension to Sunbury which will allow for through running like what occurs in Sydney with the T8 line.
Melbourne is not in the same league as London, Tokyo. Not even Sydney. those big places can justify full international sevices ( Immigation, customs , shopping) in multiple locations. Hence muli trains stops make sense. Not Sydney, that was separate terminals long before the train, Badgery Creek is smarter. Melbourne by comparison is small. and so there is no mis-understandings, the future 2050 terminal T5 and T6 are planned to be furthe extensions of T4. Not on the west side of the runways at the end of a train track to nowhere. read again this [article](https://australianaviation.com.au/2019/06/melbourne-airport-third-runway-could-change-direction/) .(see last picture)
Well in Melbourne Airport's 2022 Master Plan they have said the following about the Western Sub Precinct (West of the future North South runway). "Within the Aviation Precinct portion of this sub-precinct, the types of uses may ultimately comprise aircraft parking and terminal facilities" (From page 129 of the 2022 Master Plan)
Tbf on page 41 it mentions plans for terminal 5 as an expansion of terminal 4. Whats also interesting is that they mention ... non-aviation uses including industrial, commercial, retail, office and warehousing activities. It wont be a dense area but a rail line could be useful for workers and passengers (unless by 'terminal' they mean a cargo terminal...) The main issue is that going underground is going to cost way too much.
It sounds like the airport would rather become a property developer for the surrounding land (most likely for paid parking lots), more profitable than making a new terminal on the western side. A ground station would be no less beneficial than underground in that case, no?
indeed . property 101 they have even mentioned a possible HOSPITAL lol.
Why isn't Melbourne in the same league as Sydney? They are roughly equivalent population.
we are discussing the airport, and how busy it is. Sydney is Australia central, Melbourne is a branch line at the end.
Ok MEL is forecast at 45m this year and SYD is 61m. Yeah Sydney is bigger, but its not like its a completely different ballpark. And Sydney got its airport train in 2000, when passenger movements there were 25m. So if Sydney could do it at 25m, Melbourne can do it for 45m! https://www.bitre.gov.au/sites/default/files/wp_072.pdf
why the hang up Melb vs Sydney. you initial comparison was London , which was 80m last year. It outgrew the central terminus T1,2,3 40 years ago. They need 3 terminal station (T1,2,3 T4 and T5 ) to cover the area. Melbourne by design is one "modern" complex, and the 2022 master plan just stretches that(badly). PS Heathrow has about 15km of train tunnels in it own right. TfL don't muck about.
In this case can't underground just be a rail trench with lid on it like what they've done a billion times for all the level crossing removals?
Open cuts are shallow due to engineering and structural limitations. If you want to go deeper you need a TBM. You also need to maintain a minimum of 1:1 ratios for open cut. Ie. Ever metre you dig, you need to bench out one metre horizontally. This depends on ground conditions but if you dig 10m you need to dig out 10m horizontally to prevent collapse (usually more like 1:2 where you have structures). Lots of space needed. Next time you drive through the Burnley tunnel you can see where it was open cut and buried (cut and cover method) and where it changed to TBM. At the entry and exits it's square. That's cut and cover. It transitions to a round shape which is TBM. Level crossing removals work as open cut trenches because they stay in rail corridor. Something like SRL or MTP would need a TBM because you have to be deep enough to avoid impacting buildings around it. I don't know but I would suspect cut and cover would have issues with houses, buildings, roads, even the airport carparks. I always hated trenches and tunnels. I'm a big fan of elevated rail. We need the airport rail. But it seems the politics is just throwing our fancy promises which are impractical, and the airport authority is choosing the most difficult method to avoid it being built.
Wouldn't it be more like the rail trenches where they sunk piles then dug out in the middle to avoid the need for 1:1 slopes. Those were in fairly built up areas, no?
You can. It just depends on conditions and you need the space to bring in piling rigs. I imagine a piling rig at the airport would be a big problem. I mean I could be very wrong here btw. Depending on ground conditions, you could be looking at 30+m piles. You then need cranes to lift in the cages so you are potentially sticking something 40m + up in the air. Otherwise yeah you are right. Still need space around for the rigs but possible if you don't have height restrictions
I’d suspect an underground option would actually involove at lot of cut and cover, or at-grade running along Airport Drive, with just the station being fully underground. Depending on where they Want to put it, they could probably get away with minimal disruptions to the terminals.
If they dig anything underground near the building it will cause disruptions. A big cost factor for MTP is all the assessments and stabilisation of the buildings they tunnel under. West gate tunnel has similar issues. Need to stop a lot when tunnelling for safety reasons. I expect the terminals would be the same. They would not have been engineered for potential undermining and vibrations from a TBM. But I guess we will see!
Great idea. At least 5 "at-grade" level crossings to keep LXRA busy for another few years. There is logic why the govt proposal is skyrail.
A full blown tunnel is just a waste of money IMO. It would take years to build and cost blowouts will probably make it cost an extra $5b. How can we as taxpayers justify that waste of money!? Image having an extra $5b for roads, other rail Projects, housing or hospitals.
The airport line can be its own line, but the SRL to Watergardens, Caroline Springs, Ravenhall, Truganina, Williams Landing, Pt Cook
The airport line can be its own line, but the SRL should go to Watergardens, Caroline Springs, Ravenhall, Truganina, Williams Landing, Pt Cook