To me, this just highlights what a big white elephant the NWRL & 2nd crossing are.  All of this work is essentially to solve the problems created by the incompatible format.

My alternate solution:
- Upgrade Sector 3 to support 24tph (and ultimately 10car 200m trains) with improvements to Town Hall & Wynyard Stations (ie more platform egress points) ... ie 30kPAX per hour to start with, increasing to 36kPax/hr.  (NB this is sort of planned anyway, to cope with the NWRL metro prior to the second crossing), with express operation Central to Parramatta (hopefully down to 15min, though this would require some track upgrades & removal of)
- Re-align the tracks west of Redfern so Sector 3 takes the Mains, Sector 2 the suburbans & locals, but the locals feeding the east side of the circle rather than the west.
- Bring Gosford - Springfield into the SydneyTrains Zone, and operate them exclusively through Sector 3 across the SHB.  (With peak services starting at Lawson & Wyong, the latter to keep Shane happy ).
- Shift Epping-Strathfield to Sector 2.  Hornsby - Epping runs as a 4 car shuttle.

To create the 4th sector:
Stage 1: quad Central to St James by extending the Eddie ave viaduct to Wentworth Ave then under Oxford St connecting with Bradfield's existing tunnels into the original platforms 2&3 at St James.  This takes Inner West & Bankstown trains - could be operated as a Metro - or existing format prior to the second crossing.
Stage 2: extend the tunnels beneath Macquarie to a new station beneath Bridge Street
Stage 3: extend to Barangaroo
Stage 4: extend beneath the harbour to Chatswood to connect to the NWRL - but only *after* Nth Sydney - Hornsby is quaded.

In the interim, have the NWRL/CityRail interchange at Epping (with a peak capacity of 12tph on CityRail being fed by a similar metro service from the NWRL).

The advantage of building underground as SD is basically its cheaper per km, 20% more dirt to add another 0.5m radius, hence I don't see major new works being done as DD unless its too intergrated, like the airport line and this is similar to OS experience and probably the main driver for making the NWRL metro as much of its UG and and the extension to the city is going to be near 100% UG. Had it been on the surface it would have probably been alot different.

You are quading the NSL and building a tunnel to Chatswood? Expensive? Just so yo can run on the Central Coast services?

My proposal to rebuild the inner west local as a Metro is about 9 to 10km of tunnels. This clears the inner west local for longer haul suburbans from SW and capacity for Straithfield to Paramatta stoppers. This would pull some traffic off the main west middle tracks to enable the western express style operation for all suburban trains travelling beyond Paramatta stopppping Redferm, Straithfield, Lidcombe, Granville, Paramatta. 14t/hr

Trains beyond Paramatta would be made up of the Express services only to Richmond and Emu Plains, stopping all stops to both directions or Western Airport.

All stoppers from city on southern tracks would be Redfern, Newtown(?), Ashfield, Burwood, Straithfield, Homebush, etc all to Westmead (Maybe Blacktown). Clyde would be closed. The same tracks would be used for trains to Liverpool/Glenfield via both Granville and Reagents parks with same stopping pattern.

The remainder of the capacity could be used by Nth Line services (6t/hr)  

Western Airport Services which would have same stopping patterns as other services on the western line, except it continues to Airport where it then heads back to the city via SWRL and East Hills running limited express from Glenfield Wolli Creek to and then Mascot Airport and city, thus forming a bi-directional circular route connecting the airports, Paramatta and the city.

Central Coast and Mountains interurban would remain on the Nth tracks, however I would significantly upgrade Redfern to Central. Currently trains are crossing each other on a spaghetti layouts of tracks feeding the various stations and at same time some regional trains are thrown into the mix. Arrivals and departures would be separated vertically until just prior to the platform for the spark services to reduce the conflicting moves.   I'd also add mid station cross over to the central track to increase station capacity for the shorter train services, like Country Link.

As for tunneling, what does cheaper mean in this case, short term or long term? Remember that the NWRL was originally planned as an extension of the existing suburban railway network, those plans were changed when Rodd Staples was put in charge.

As for tunneling, what does cheaper mean in this case, short term or long term? Remember that the NWRL was originally planned as an extension of the existing suburban railway network, those plans were changed when Rodd Staples was put in charge.

The Metro technology is cheaper to tunnel, cheaper to buy the trains and cheaper to operate.

The NWRL is not the first attempt at introducing this approach to Sydney, the last was by the previous govt on the inner NW Metro.

The reality for Sydney is that the bulk of the expansion of the inner suburban network will be via tunnel, hence the technology that is used to run in that tunnel is going to have a huge impact on cost. Its not like you are simply joining the dots over a few km. Its likely over the next 30 years there will be over 50km of inner suburban rail lines built to improve capacity for the growing inner and outer urban regions of Sydney. The system is no longer running like a regiona suburban network with frequencies on most of the inner network pushing 20t/hr.

Another previous attempt was the CBD metro, both that and the North West Metro were Rodd Staples' plans. As far as I know, Mr. Staples' first experience with rail planning, construction and operations was in 2005 when he was hired by Rail corp.
Both those plans were to recreate the metro-suburban divide that John Bradfield intended to avoid, as noted in this article.

Another previous attempt was the CBD metro, both that and the North West Metro were Rodd Staples' plans. As far as I know, Mr. Staples' first experience with rail planning, construction and operations was in 2005 when he was hired by Rail corp.
Both those plans were to recreate the metro-suburban divide that John Bradfield intended to avoid, as noted in this article.

John Bradfield was a brilliant Engineer in his time, time has since moved on! Technology has changed, commuting dynamics have changed, a hell of alot has changed!

The Metro-Suburban divide is the back bone of many city in the world and growing and cities that are often held up as example of high standard PT.

You cannot support the growth on the inner half of the network at the same time as serving the outer half growth on the same tracks or even corridors in most of Sydney any more, things need to change! The easy fixes and capacity creep enhancement is quickly running out. We need new corridors and new track and in most cases this will be UG, and not for a few km as per the past, but half way across the city and this includes new corridors through the city itself If one technology costs at least 10% more than another and yet the total capacity is similar, then guess what we need to do?

The metro suburban divide is the backbone of cities like Paris and London, which had metro before suburban rail, and the overground in the latter only began quite recently, only in the middle of last decade.
These cities were also quite heavily developed when the railways came, and metro was seen as a way to avoid the great cost and inconvenience of extending regional railways right into the middle of town, especially with the technology of the time. Regional railways, which were all steam hauled back then, would terminate on the outskirts of town and passengers would change to electric trains typically running underground.
Time had already moved on, and technology already changed when Bradfield helped bring heavy suburban rail right into the CBD of a later developing city.
One easy fix to the greatest bottleneck would be just two extra tracks on the Harbour bridge, at least according to EcoTransit.

If you cannot support growth on the inner half of the network on the same tracks serving the out half, maybe we need more light rail lines.

As for changes since Bradfield's time, back then, Sydney had many (coupled) toastrack trams, but today, OH&S would rule them out. Might the existing suburban railway network and its double decker trains go the way of toastrack trams?

The metro suburban divide is the backbone of cities like Paris and London, which had metro before suburban rail, and the overground in the latter only began quite recently, only in the middle of last decade.
These cities were also quite heavily developed when the railways came, and metro was seen as a way to avoid the great cost and inconvenience of extending regional railways right into the middle of town, especially with the technology of the time. Regional railways, which were all steam hauled back then, would terminate on the outskirts of town and passengers would change to electric trains typically running underground.
Time had already moved on, and technology already changed when Bradfield helped bring heavy suburban rail right into the CBD of a later developing city.
One easy fix to the greatest bottleneck would be just two extra tracks on the Harbour bridge, at least according to EcoTransit.

If you cannot support growth on the inner half of the network on the same tracks serving the out half, maybe we need more light rail lines.

As for changes since Bradfield's time, back then, Sydney had many (coupled) toastrack trams, but today, OH&S would rule them out. Might the existing suburban railway network and its double decker trains go the way of toastrack trams?

Sir John Bradfield died in 1943 during a time when the world had other things to focus than building suburban railways in a colony. Alot has changed technology wise as has Sydney since then.

Light Rail is a poor substitute to heavy rail especially over longer distances especially if confined to mostly road based corridors. SSELR travel time versus extension of ESR is case in point.

The so called "quick fix" for the harbour bridge barely even acknolwedges the issues either side of the bridge, just that two lanes used to hold trams, so lets make it a railway again aproach. Also fails to identify what the traffic that currently uses those two lanes will do? Bradfield proposed that the former tram lines on the bridge would be the Nth Beach RL and into Wynyard, but then what? The work to build more tunnels was never even started and then what about the Nth side? Sure you can run 4 tracks up to St Lenoards without a huge expense, but then the pain starts and note this route is a goat track, so do we want four tracks on the goat track?

I don't see any major reason to replace the DD network apart from a few locations where its convenient to convert to Metro, ie
- Carlingford Line, replace with EPRL as an extension of the Metro network
- Bankstown Line to Reagents Park, as part of the cross Sydney Metro
- Inner West stations, as part to capacity increase on the existing inner western main corridore. ie push the all stoppers onto a new set of tracks.
- Potentially, connect the dots by extending the Metro from Straithfield to Olypmic Park and around to Lidcome and connect to Reagents Park, however this existing HR route through this area would remain for Liverpool-Campbelltown services, removal some stations for these services would speed the SW services up, slightly.
- I'd also propose the future NW line to Epping from Ashfield or Newtown and Nth Beaches off Sydney Metro from Nth. All this balances out the new network.

New airport should be connected from Nth and Sth with DD services.

Light Rail is a poor substitute to heavy rail especially over longer distances especially if confined to mostly road based corridors. SSELR travel time versus extension of ESR is case in point.

But you said that metro was better suited to shorter distances than heavy suburban rail, and here is where light rail comes into it.

The so called "quick fix" for the harbour bridge barely even acknolwedges the issues either side of the bridge, just that two lanes used to hold trams, so lets make it a railway again aproach. Also fails to identify what the traffic that currently uses those two lanes will do? Bradfield proposed that the former tram lines on the bridge would be the Nth Beach RL and into Wynyard, but then what? The work to build more tunnels was never even started and then what about the Nth side? Sure you can run 4 tracks up to St Lenoards without a huge expense, but then the pain starts and note this route is a goat track, so do we want four tracks on the goat track?

But there is space in the rail easement between Chatswood and St. Leonards for those two additional tracks so only a short tunnel would be needed.

I don't see any major reason to replace the DD network apart from a few locations where its convenient to convert to Metro, ie
- Carlingford Line, replace with EPRL as an extension of the Metro network
- Bankstown Line to Reagents Park, as part of the cross Sydney Metro
- Inner West stations, as part to capacity increase on the existing inner western main corridore. ie push the all stoppers onto a new set of tracks.
- Potentially, connect the dots by extending the Metro from Straithfield to Olypmic Park and around to Lidcome and connect to Reagents Park, however this existing HR route through this area would remain for Liverpool-Campbelltown services, removal some stations for these services would speed the SW services up, slightly.
- I'd also propose the future NW line to Epping from Ashfield or Newtown and Nth Beaches off Sydney Metro from Nth. All this balances out the new network.

How about OH&S issues? I mean under future regulations. You did give a health and safety reason why no one makes automated double decker trains.

But you said that metro was better suited to shorter distances than heavy suburban rail, and here is where light rail comes into it.



But there is space in the rail easement between Chatswood and St. Leonards for those two additional tracks so only a short tunnel would be needed.



How about OH&S issues? I mean under future regulations. You did give a health and safety reason why no one makes automated double decker trains.

But you said that metro was better suited to shorter distances than heavy suburban rail, and here is where light rail comes into it.

Metro is better suited to all stopping services with Stations close together like the London Underground. Light Rail never is and should never be a replacement for a Metro. To illustrate, the Docklands Light Rail was built serving Canary Wharf. It has been subsequently much enhanced, but even that could not cope with the numbers working there and so a full scale Metro (Jubilee Line extension) was built.

Michael

And metro never is nor should be a relpacement for heavier rail, such as suburban rail. Legacy metros have station spacing less than a mile and often more than one per suburb, often not much greater than world class light rail.
My point is, if we need something other than heavy suburban rail for shorter services in the inner city, it may as well be light rail.

But you said that metro was better suited to shorter distances than heavy suburban rail, and here is where light rail comes into it.



But there is space in the rail easement between Chatswood and St. Leonards for those two additional tracks so only a short tunnel would be needed.



How about OH&S issues? I mean under future regulations. You did give a health and safety reason why no one makes automated double decker trains.

Issue with Automated DD train technology is that no one that I am aware of is building it. The reason for that is because Automated SD train technology is cheaper and can delivery the same capacity albeit more in standing capacity than sitting. DD cars to be efficient and loading and unloading like Paris RER need to have very long cars to get the extra doors in and these east into seating capacity big time?

And metro never is nor should be a relpacement for heavier rail, such as suburban rail. Legacy metros have station spacing less than a mile and often more than one per suburb, often not much greater than world class light rail.
My point is, if we need something other than heavy suburban rail for shorter services in the inner city, it may as well be light rail.

@Myrtone, it is far too simplistic to advocate replacing heavy suburban rail with Light Rail. Granted there are two lines that could be converted to light rail, (Altona Loop and Williamstown Lines in Vic). If patronage is greater than can be handled by Heavy Suburban rail within the Inner City than only a Heavy grade separated metro can handle those numbers, light rail could not handle large numbers of commuters. A case in point, the 96 Tram route in Melbourne is struggling to meet demand, and with light rail it is not easy to expand capacity.

In Sydney the Conversion of the Metropolitan Goods line was converted to Light Rail because it was much cheaper to do so.

What is an example of World Class Light Rail. Surely not the Manchester Metrolink?


Michael

I'm not advocating such a replacement, or anything really. Fact is that someone said that the existing heavy suburban rail needs to supplamented by another form of rail more suitable for shorter trips, and that's where light rail fits well.

Fact is that heavy suburban rail has a capacity no less than a metro, I know it may be hard to believe, but with improved signalling that does apply.

I'm not advocating such a replacement, or anything really. Fact is that someone said that the existing heavy suburban rail needs to supplamented by another form of rail more suitable for shorter trips, and that's where light rail fits well.

Fact is that heavy suburban rail has a capacity no less than a metro, I know it may be hard to believe, but with improved signalling that does apply.

No I (assume me) didn't say that.

I said to words of effect.
That new Greenfield built lines and major expansions in the inner suburban and city area will be mostly/totally underground and hence far more costly to build and cost saving options including building Metro style. This will basically mean a 2nd rail network for Sydney, however if cost reductions of at least 15% can be achieved in CAPEX and over the life of 1st generation trains that should exceed 30 years service life, this I believe its worth it. It is also inline with many other major cities.

As part of this roll-out and to resolve other capacity and efficency issues at the same time, some lines or sections track of the current system will need to be converted to Metro as well. In some of the proposals this would need to occur anyway to improve capacity/de-bottleneck either on that section of track directly or indirectly further down the line where the capacity constraint occurs.

SD at 30t/hr can move near similar numbers as DD at 20t/hr for similar length using Sydney's 20m car length. So long term capacity is not effected. For the less dense areas of the new Metro, frequencies can be reduced, however being Auto, they do not need to be reduced to the same extent as manual trains as their running costs are cheaper, ie no driver or guard.

In the case of the NWRL, its more an orbital route with multiple junctions and the average commuter will not be undertaking the longer city focused commute like many other Sydney routes, hence the reduced seating capacity is less of an issue than other lines.

That new Greenfield built lines and major expansions in the inner suburban and city area will be mostly/totally underground and hence far more costly to build and cost saving options including building Metro style. This will basically mean a 2nd rail network for Sydney, however if cost reductions of at least 15% can be achieved in CAPEX and over the life of 1st generation trains that should exceed 30 years service life, this I believe its worth it. It is also inline with many other major cities.

But the dual system of metro and suburban rail is quite rare and most cities that have it had the metro before suburban rail, can you acknowledge that and see what difference that makes? Same with these cities being heavily developed by the time that the railways came.

Cities like London, Paris and Berlin have extended or are extending suburban rail into and through their city centres and there is a trend away from the metro suburban divide. Nowhere else in the world are larger suburban trains with many seats being replaced by metros with fewer seats still travelling 20km or more.

But the dual system of metro and suburban rail is quite rare and most cities that have it had the metro before suburban rail, can you acknowledge that and see what difference that makes? Same with these cities being heavily developed by the time that the railways came.

Cities like London, Paris and Berlin have extended or are extending suburban rail into and through their city centres and there is a trend away from the metro suburban divide. Nowhere else in the world are larger suburban trains with many seats being replaced by metros with fewer seats still travelling 20km or more.

Rare, No, far from it and the answer is no, not all had Metro before and so what if they did? German cities built the U-bahn by and large to replace war torn and aging tram networks and to cater for the increases masses living in the inner city

Why does it make a difference? You had one, the city changed, time to build some more, did the legacy system technology suit the expansion? Yes/No. Even in Paris they have built newer Metro lines with different non-compatible technology and in some cases upgraded with additional non-compatible technology? Numerous cities have non-compatible HR networks because once you are over a certain size there is no cost benefit and lines are increasingly run at high capacity with all trains on same point to point and to not share other corridors like Sydney CBD. Again Paris, Vancouver, Singapore, London to name a few.

Sydney is only replacing on short legs of the network because it helps joins the dots in building the Metro. It not a large scale replacement nor is anyone recently promoting the same. The previous proposal to replace much of the network with SD's is long dead. Melbourne replaced Heavy Rail with Light Rail, twice! Vancouver built Metro over the top of former HR alignment and potentially its only HR commuter corridor will be closed to commuter in favour of a new Metro.

In reference to other cities building suburban networks into the city, this is to cater for growing sprawl for cities you mention would have an historic small geographic high density development, tunnelling a few km or so is probably not overly expensive in comparison to the number of people that line will move. However Sydney has a legacy surface suburban low density network for a city the is geographically one of the largest in the world but still barely considered a medium population. However with growing inner density things are changing. New surface lines can no longer be built as the land isn't available and every thing is UG and over long distances.

As I have stated before, it all gets down to cost! and if cost of building a DD UG line is more than 15% more than Metro, then its too expensive longterm and only going to hold the PT expansion back. There is nothing wrong with the Auto Metro technology which is why its expanding at a larger rate including Vancouver and Dubai which have the largest Auto lines in the world and move more people on one line than Sydney does with half a network.

From 99 years ago: Bradfields 1916 report

Definition of Metro from Wiki

Considerations[edit]
The International Association of Public Transport (L'Union Internationale des Transports Publics, or UITP) defines metro systems as urban passenger transport systems, "operated on their own right of way and segregated from general road and pedestrian traffic".[4][5] The terms Heavy rail (mainly in North America) and heavy urban rail are essentially synonymous with the term "metro".[6][7][8] Heavy rail systems are also specifically defined as an "electric railway".[6][7]

The dividing line between metro and other modes of public transport, such as light rail[6][7] and commuter rail,[6][7] is not always clear, and while UITP only makes distinctions between "metros" and "light rail",[4] the U.S.'s APTA and FTA distinguish all three modes.[6][7] A common way to distinguish metro from light rail is by their separation from other traffic. While light rail systems may share roads or have level crossings, a metro system runs, almost always, on a grade-separated exclusive right-of-way, with no access for pedestrians and other traffic. And in contrast to commuter rail or light rail, metro systems are primarily used for transport within a city, and have higher service frequencies and substantially higher passenger volume capacities. Furthermore, most metro systems do not share tracks with freight trains or inter-city rail services. It is however not relevant whether the system runs on steel wheels or rubber tyres, or if the power supply is from a third rail or overhead line.

The name of the system is not a criterion for inclusion or exclusion. Some cities use metro as a brand name for a transit line with no component of rapid transit whatsoever. Similarly, there are systems branded light rail that meet every criterion for being a rapid transit system. Some systems also incorporate light metro or light rail lines as part of the larger system under a common name. These are listed, but the light rail lines are not counted in the provided network data. Certain transit networks match the technical level and service standards of metro systems, but reach far out of the city and are sometimes known as S-Bahn, suburban, regional or commuter rail. These are not included in this list. Neither are funicular systems, or people movers, such as amusement park, ski resort and airport transport systems.
....................................


I think the simple answer to the Metro technology questions for Sydney is
- Is it part of a future large most UG network? Yes!
- Is it cheaper to build SD UG than DD? Yes!
- Do other cities build large scale UG networks based on DD technology, No!
- Do any of the Mainstream Metro train suppliers supply Automated/Semi-auto train services in DD format? No

Another previous attempt was the CBD metro, both that and the North West Metro were Rodd Staples' plans. As far as I know, Mr. Staples' first experience with rail planning, construction and operations was in 2005 when he was hired by Rail corp.
Both those plans were to recreate the metro-suburban divide that John Bradfield intended to avoid, as noted in this article.

I didn't read all of it but skimmed and read some parts in detail and it didn't impress me too much

- Reference to train being a tight fit in new tunnels creating the piston effect. Last time I went into Sydney tunnels, thats exactly what you get now. Put trains in a tunnel spaced 2-5min apart and you will always create a tunnel wind. Also platform doors helps reduce impact on passengers. How about we let the train designers do their job.

- Wanting to use the 2nd harbour crossing as part of a regional network. So great, we are going to screw another corridor by mixing local and express services. Look at SW line via Straithfield to see how much damage this does to track capacity

- Complaints about the safety of trains because they are SD vs DD. Dubai, Vancouver, Singapore move more people per day on fully automated "light weight" trains if that's what they are than Australian networks combined and have an impressive safety record.

- standing, current 25 to 50% of pax on many lines in Sydney are standing on arrival to CBD and there are no plans correct this in most cases any time soon. Worse still many bus pax are doing the same. Provided the average standing time on NWRL does not exceed the average time by other lines then its obviously ok. What next, booked seating?

- Is it Lawful? Seriously!

I didn't read all of it but skimmed and read some parts in detail and it didn't impress me too much

You should read it all, and you should think about the points he's making more broadly.  

IMHO, he's suggesting NSW rail planning process is flawed, because it's taking the same top-down approach an enthusiastic amateur might from the other side of the world .

I don't agree with everything he says either, and he is (perhaps understandably because he was involved with the planning process) overly defensive of the MREP from the mid 2000s.  

But the core theme is that plan was arrived at by analysing the problems from the bottom up, and devising a solution utilising what is available as best possible.

The issue we've had in NSW is too much of the planning occurs from the top down, either politicians drawing lines on maps, or senior bureaucrats pushing ideological barrows.

Rare, No, far from it and the answer is no, not all had Metro before and so what if they did? German cities built the U-bahn by and large to replace war torn and aging tram networks and to cater for the increases masses living in the inner city

In the research I've done, most did, inculding London, Paris and Berlin. A number of German cities have both S-bahn and U-bahn, but accroding to my reading, the U-bahn tended to come first. The Paris Metro, for example, began in 1900, and that in Berlin began only two years later. Berlin's S-bahn began 24 years later and the Paris RER 69 years later.

Why does it make a difference? You had one, the city changed, time to build some more, did the legacy system technology suit the expansion? Yes/No. Even in Paris they have built newer Metro lines with different non-compatible technology and in some cases upgraded with additional non-compatible technology? Numerous cities have non-compatible HR networks because once you are over a certain size there is no cost benefit and lines are increasingly run at high capacity with all trains on same point to point and to not share other corridors like Sydney CBD. Again Paris, Vancouver, Singapore, London to name a few.

There are 14 metro lines in Paris and lines 1-13 all predate the RER. Why does it make a difference? If you already have an established metro network by the time your suburban services began, as in Paris in 1969, you can buy and run new metro rolling stock over 30 years, or maybe more, for only a fraction of the price of converting them for use by suburban trains, which would involve enlarging tunnels and possibly consolidating stations. The price difference is likely to be greater than between (a) regauging existing tram and metro systems built to uncommon track gauges and (b) buying and running customised rolling stock to suit the unusual track gauges.

Vancouver, Singapore and Dubai seem to have no commuter rail at all, only metro.

- Reference to train being a tight fit in new tunnels creating the piston effect. Last time I went into Sydney tunnels, thats exactly what you get now. Put trains in a tunnel spaced 2-5min apart and you will always create a tunnel wind. Also platform doors helps reduce impact on passengers. How about we let the train designers do their job.

-The wind effect is greater in smaller tunnels than larger ones. And I'm sure platform doors could be fitted to stations on a legacy suburban rail network, OCLAP has a solution.

In the research I've done, most did, inculding London, Paris and Berlin. A number of German cities have both S-bahn and U-bahn, but accroding to my reading, the U-bahn tended to come first. The Paris Metro, for example, began in 1900, and that in Berlin began only two years later. Berlin's S-bahn began 24 years later and the Paris RER 69 years later.


There are 14 metro lines in Paris and lines 1-13 all predate the RER. Why does it make a difference? If you already have an established metro network by the time your suburban services began, as in Paris in 1969, you can buy and run new metro rolling stock over 30 years, or maybe more, for only a fraction of the price of converting them for use by suburban trains, which would involve enlarging tunnels and possibly consolidating stations. The price difference is likely to be greater than between (a) regauging existing tram and metro systems built to uncommon track gauges and (b) buying and running customised rolling stock to suit the unusual track gauges.

Vancouver, Singapore and Dubai seem to have no commuter rail at all, only metro.


-The wind effect is greater in smaller tunnels than larger ones. And I'm sure platform doors could be fitted to stations on a legacy suburban rail network, OCLAP has a solution.

Berlin yes
Hamburg sort of. Note regional trains don't stop at suburban stations.
Colonge No
Munich No
Numerberg No

The last three are following the Sydney approach, using Metro to replace previous tram network, bus and areas not well served by S-bahn and not suited to additional S-bahn lines.

Vancouver has a surface commuter line apart from its Automated metro system, Skytrain. The newest line is the Canada line and not compatible with previous Skytrain lines. The Skytrain was partly built over the former ROW of HR.

Singapore has multi metro's not compatible with each other.

Dubai has one technology for the largest Auto Metro in world as it was built at the same time. Whether the same technology is used again is a question.

I believe there has been little attempt in Paris to standardise because the trains required operate on Line X line only operate on Line X, Not X to Y or Z to X. Each new line used the most suitable technology for the day and they have little interest in standardising as the system is big enough.

I'd be highly surprised if the wind from the tunnel is worse than now, it can be controlled numerous ways including ventilation shafts to allow the tunnels to breath and platform doors which they are getting anyway. The appears little interest to install platform doors on existing so I see this as a non issue unless you are standing on the platform side with a loose flowing dress or skirt, read Marilyn Monroe.

As for the cites you have mentioned, Cologne has no heavy metro, just a light rail network that runs underground in the core of the city, with high platform loading.
Munich's U-bahn dates back to 1971 and the S-bahn began a year later. Nuremburg's U-bahn began the same year as the S-bahn in Munich, and the Nuremburg S-bahn began 15 years later.

As for standardisation in Paris and Singapore, I'm sure that the lines are all still physically compadible, except for the rubber tyred metro lines in Paris, it's all conventional rail, using standard gauge.
An even in Paris, such standardisation does seem to apply to the RER, newer than the metro.

EDIT:I predict that underground stations on the existing suburban network are going to also need platform screen doors of some description.

As for the cites you have mentioned, Cologne has no heavy metro, just a light rail network that runs underground in the core of the city, with high platform loading.
Munich's U-bahn dates back to 1971 and the S-bahn began a year later. Nuremburg's U-bahn began the same year as the S-bahn in Munich, and the Nuremburg S-bahn began 15 years later.

As for standardisation in Paris and Singapore, I'm sure that the lines are all still physically compadible, except for the rubber tyred metro lines in Paris, it's all conventional rail, using standard gauge.
An even in Paris, such standardisation does seem to apply to the RER, newer than the metro.

EDIT:I predict that underground stations on the existing suburban network are going to also need platform screen doors of some description.

Colonge's underground system is part of the light rail network (which I have used) and is just as much a UG network as any other. Double sided platforms per track, high level platforms.

Ok, I didn't check the actual dates for the S-bahn, but I read a bit more now and to say there was no surface rail network before is not quite true. It just wasn't as extensive or developed back then.

Singapore and Paris, excluding the rubber tyre issue. No many of the lines are not comparable. Gauge is same, but in many cases that is about it. Unless the lines are compatible they are unlikely to even be connected. Certainly the Canada line in Vancouver has no rail connection to the rest of the Skytrain network, Singapore's NE line is not connected, likewise no part of Skytrain is connected to the HR network also used by the only HR commuter service.

The RER is a common suburban/outer suburban network. Not sure what your point is here when of the 14 or so Metro lines, many are non-compaitable with each other and none with the RER. In most cases none of the U-bahn's are compitable with the S-bahns and the list goes on. Do you want me to mention more cities? New York Subway versus the regional network trains?

The argument is still the same. Where you cannot practically build a Surface railway you go underground. Going UG is expensive and when the bulk of a line or new network is UG, you don't use high profile rail vehicles because the tunnels need to be larger and with size comes cost. London tube being the far end of the practical scale of making as small as possible. 5.5m tunnel vs 6m tunnel is 19% more material to be excavated and takes longer and requires more concrete, this comes at a large cost. We are not building a few km of the CBD section underground where the bulk of the network is surface. We are building a line that is UG from basically fringe of current suburbia to sth of CBD 20-30km. Its likely by 2035 the UG route km will exceed 100km.

The only exception to the above and I saw this with the SLR before the last extension was that at terminus there was still a rail connection which I understand was for use by track vehicles only. Looking at the latest sat photos of the extension to Dulwich Hill there is no longer a connection to the HR network.

While I agree on the screen doors, you have to wonder why some stations will get screen doors, ie the new Auto Metro and the legacy network won't. I don't see them doing the UG as this opens a large can of worms for other stations. Driver or not, if something is on the tracks they train will still fail to stop in time.