Actually the concrete piers the new bridge spans sit on were built in the 1960s and it wasn’t until 1980 spans were floated onto piers to replace original bridge. Certainly wouldn’t see such forward thinking these days to allow for 4 tracks crossing parramatta river.

Just to add to that and my earlier comment, the existing spans on the eastern side of the John Whitton Bridge currently accommodate the Main Line tracks.  When the spans are installed on the western side as part of the quadruplication, the current Up Main will be slewed to the Down Main across the bridge and the Up Relief will take over the Up Main track.  Conversely in the Down direction, the current Main will run across the new span together with the Relief Line.

Past rail planners and governments had shown a lot of foresight in allowing for future track amplifications, such as for the Northern, Western and North Shore Lines.

I always thought that the track centres on the JW Bridge are quite narrow and wider stock cannot pass whilst on the bridge. Were the piers as built intended for 2 or 4 tracks?

Actually the concrete piers the new bridge spans sit on were built in the 1960s and it wasn’t until 1980 spans were floated onto piers to replace original bridge. Certainly wouldn’t see such forward thinking these days to allow for 4 tracks crossing parramatta river.

Just to add to that and my earlier comment, the existing spans on the eastern side of the John Whitton Bridge currently accommodate the Main Line tracks.  When the spans are installed on the western side as part of the quadruplication, the current Up Main will be slewed to the Down Main across the bridge and the Up Relief will take over the Up Main track.  Conversely in the Down direction, the current Main will run across the new span together with the Relief Line.

Past rail planners and governments had shown a lot of foresight in allowing for future track amplifications, such as for the Northern, Western and North Shore Lines.

I always thought that the track centres on the JW Bridge are quite narrow and wider stock cannot pass whilst on the bridge. Were the piers as built intended for 2 or 4 tracks?

Built for 4 tracks.  The western side spans will accommodate the other 2 tracks.

Just to add to that and my earlier comment, the existing spans on the eastern side of the John Whitton Bridge currently accommodate the Main Line tracks.  When the spans are installed on the western side as part of the quadruplication, the current Up Main will be slewed to the Down Main across the bridge and the Up Relief will take over the Up Main track.  Conversely in the Down direction, the current Main will run across the new span together with the Relief Line.

Past rail planners and governments had shown a lot of foresight in allowing for future track amplifications, such as for the Northern, Western and North Shore Lines.

There are no spans on the eastern side of the john whitton bridge. The new bridge and the ability to expand to 4 tracks is on the western side of the john whitton bridge.

A third track should be a no brainer from rhodes to west ryde.

I think the newer bridge is named the “John Whitton Bridge”, in this context, Transtopics comments make sense.

The old bridge was built when Whitton was in charge, so can also be called a “John Whitton bridge”

I think the newer bridge is named the “John Whitton Bridge”, in this context, Transtopics comments make sense.

The old bridge was built when Whitton was in charge, so can also be called a “John Whitton bridge”

I have only ever known the old bridge to have been called the john whitton bridge. As far as I am aware the new bridge has no name.

https://en.m.wikipedia.org/wiki/John_Whitton_Bridge

I think the newer bridge is named the “John Whitton Bridge”, in this context, Transtopics comments make sense.

The old bridge was built when Whitton was in charge, so can also be called a “John Whitton bridge”

I have only ever known the old bridge to have been called the john whitton bridge. As far as I am aware the new bridge has no name.

The 'new' bridge is the Whitton bridge; the old one was always referred to as the Meadowbank bridge. Whitton designed many bridges in many styles, they are not all known as Whitton bridges.

A third track should be a no brainer from rhodes to west ryde.

Well it will actually be a third AND fourth track which will complete quadruplication between Strathfield and Epping.

Speaking of doing a Hornsby-Strathfield quad, I actually wonder what are/would be the speed limits on the outer lines? What are the current speed limits on the down relief/3rd track? 80km/h? If the line is to get quad and the express passenger trains, such as intercity and regional are to use it between freight services, it would be preferable if it would allow for 115km/h running line the main/middle lines do through some sections.

Also further to that, would there be any real benefit gained to triplicate/quad the line further to Berowra in the future? I guess this could remove the suburban trains out of the way from intercity and regional trains all the way through the corridor and give further options for freight running.

Speaking of doing a Hornsby-Strathfield quad, I actually wonder what are/would be the speed limits on the outer lines? What are the current speed limits on the down relief/3rd track? 80km/h? If the line is to get quad and the express passenger trains, such as intercity and regional are to use it between freight services, it would be preferable if it would allow for 115km/h running line the main/middle lines do through some sections.

Also further to that, would there be any real benefit gained to triplicate/quad the line further to Berowra in the future? I guess this could remove the suburban trains out of the way from intercity and regional trains all the way through the corridor and give further options for freight running.

The speed limits vary considerably depending on where the Main and Suburban/Relief tracks merge or diverge.  The maximum speed limit on the Third Track (Down Relief) is 115km/h for a relatively short distance between Pennant Hills and Thornleigh before it merges with the adjoining Down Main (X75).  The Down Main has a similar limit in this location.  From West Ryde to Pennant Hills, the Down Main and Down Relief lines generally have similar speed limits, which can vary between 70 and 95km/h.  It's obviously a lot slower through the winding section between Beecroft and Pennant Hills.  Fast Intercity and Regional trains already use the Third Track BTW.  In the Up direction, the maximum speed limit of 115km/h is on the Main between West Ryde and North Strathfield with some sections of 95-100km/h.

The second stage of the NSFC program will complete the Third Track (Down) from Rhodes to Hornsby as well as the Fourth Track (Up) from Epping to Rhodes, in effect completing the full quad from Strathfield to Epping and triplication from Epping to Hornsby.  There's no proposal at this stage to complete the final quad section from Hornsby to Epping, although it could be part of a future stage.

Once full quadruplication is completed I would expect that the Main and Suburban/Relief tracks would have similar speed limits.  I can see no reason why the very conservative speed limits between North Strathfield and West Ryde, which is almost dead straight, couldn't be increased to 130km/h for Suburban and Intercity and 150km/h for Regional (XPT) services.

Not to deviate from the topic too much, but on speeds, has there been any mention how fast the new Intercity trains will be able to go? What type of "comfortable"/sustained top speeds would they be capable of? 140 - 150km/h perhaps?

Not to deviate from the topic too much, but on speeds, has there been any mention how fast the new Intercity trains will be able to go? What type of "comfortable"/sustained top speeds would they be capable of? 140 - 150km/h perhaps?

I believe that they will be capable of 160km/h, although the actual service speeds will probably be a lot less, at least until some of the Intercity Lines are straightened out and speed limits are upgraded generally.

To be honest overall I find it somewhat surprising that this stretch of track (Strathfield/Hornsby, or at the very least Strathfield/Epping) has yet to get the full quad given the numerous freight, regional, intercity and suburban services. I could totally see a limited stops suburban stopping at something like Epping, Eastwood, West Ryde, Rhodes, Strathfield, Burwood, Redfern, Central. Rhodes has had huge development and has a shopping center. Epping continues to grow in importance as an interchange. I saw a comment someone had made expressing concern about the amount of space left between the dive and main up at North Strathfield to re-instate the relief/outer up so that regional/intercity trains can use it to get to Strathfield un-interrupted by suburbans which can use the existing main up. Below are a few photos courtesy of highplans68 on flickr. I'm guessing they'd have to turn the Pomeroy Street Bridge to a single span if possible? because one of the supports would no doubt block the re-in statement of the up relief.

Photo from July 1990, purely for nostalgia purposes and to see the old Pomeroy St Bridge
https://www.flickr.com/photos/highplains68/8317345011/

c. 2011 before work began (credit T G for this shot)
https://www.flickr.com/photos/squeakaz/5600166708/

May 2014. Construction Work
https://www.flickr.com/photos/highplains68/14276419542/

April 2015. Just before dive opened
https://www.flickr.com/photos/highplains68/17065096857/

April 2015. Another view of dive
https://www.flickr.com/photos/highplains68/17084980560/

June 2018. View of dive as it is today
https://www.flickr.com/photos/highplains68/28656162018/

To be honest overall I find it somewhat surprising that this stretch of track (Strathfield/Hornsby, or at the very least Strathfield/Epping) has yet to get the full quad given the numerous freight, regional, intercity and suburban services. I could totally see a limited stops suburban stopping at something like Epping, Eastwood, West Ryde, Rhodes, Strathfield, Burwood, Redfern, Central. Rhodes has had huge development and has a shopping center. Epping continues to grow in importance as an interchange. I saw a comment someone had made expressing concern about the amount of space left between the dive and main up at North Strathfield to re-instate the relief/outer up so that regional/intercity trains can use it to get to Strathfield un-interrupted by suburbans which can use the existing main up. Below are a few photos courtesy of highplans68 on flickr. I'm guessing they'd have to turn the Pomeroy Street Bridge to a single span if possible? because one of the supports would no doubt block the re-in statement of the up relief.

The stretch of track between Strathfield and Epping will get the full quad, as well as triplication from Epping to Hornsby, with completion of Stage 2 of the Northern Sydney Freight Corridor program.  It's programmed to be completed within the next decade.

Limited stop peak hour services from Hornsby to Sydney Terminal will be implemented following the shutdown of the Epping to Chatswood Rail Link for metro conversion in a couple of weeks, running all stops to Eastwood, then West Ryde, Meadowbank, Rhodes, Strathfield and Central.  In the off-peak, it will be all stations to Burwood, Redfern, Central and through the CBD to the North Shore.  

Space has been reserved for reinstatement of the Up Suburban/Relief Line through North Strathfield to Strathfield, although constructing an additional platform is unlikely.