Corinda to Darra - quadruplication (Corinda precinct)

[ozbob]

No Golli, there were many millions left over.  For the paltry additional costs of around 20 million or so they could have constructed the 4th platform and electrified the up sub.  It is now estimated to be over 100 million to come back an do it by 2015 in any case.  There were even drawings done up for the 4th platform at Oxley (suspended platform).   It is the failure to get things right from the outset that is pushing back all infrastructure.  The 100 million it will now take to fix it up is less money for further necessary infrastructure. It is a cost escalating spiral. A same situation is developing with Ellen Grove station, although I am now a little more optimistic that might yet get turned around.  The fact that the freighters are still pounding the mains through Corinda is just further evidence of the botched nature of the layout.

Construction of two island platforms at Darra would have been no more costly than the present station (probably less in fact), but importantly it would have made for a much more functional station with amenities and facilities more accessible as well.

[somebody]

I don't see why Darra would have been better with two islands, if you have up-down-up-down tracks?

What would have been better is if the inbound line from Richlands went under the other tracks to the old Darra platform #3 and an additional crossover from the Down Main (old platform #2), with the outbound line coming off from the additional track.  If that made sense.

[ozbob]

Possibly, but not enough room.

I would have just kept the quad going straight through, no freight loop.  Richlands branch just goes up from the subs.

The advantage of the islands is the shared ammenties as well for pax.  The only platform with anything on it is platform 4 now.  No water toilets etc. on the other three platforms.

If you wanted to streamline transfers and so forth crossings can be easily laid.  The advantage of this is simple and avoids the criss crossing if the up sub is electrified and so forth.  Will still be achieved eventually, but if they chose to do this layout the money saved on the freight loop would have paid for the full electrification from day one ...

[somebody]

I don't see how there would be an issue with "not enough room" for the fly-under from Richlands to the old Darra platform #3?  Have a look at the old setup, still visible in Google Earth.  The rail access road may have had to be relocated though.

The parking added to the NW of the station may have had to be reduced, but I don't think this is an issue.  You could add more parking to the area on the SW of the station.

[mufreight]

I don't see how there would be an issue with "not enough room" for the fly-under from Richlands to the old Darra platform #3?  Have a look at the old setup, still visible in Google Earth.  The rail access road may have had to be relocated though.

The parking added to the NW of the station may have had to be reduced, but I don't think this is an issue.  You could add more parking to the area on the SW of the station.

Unfortunately perusal of the google mkaps does not give the elevations and shour of raising the Centenary Highway by about 4 or 5 metres the grades required to access the Richlands line would have been pretty extreme, the more logical approach would have been to electrify all four tracks allowing all all stations services to operate on the subs with an overpass for the freight services from between the main lines to the west of Corinda in the region of Allan Terrace crossinf the up main both the up and down subs and junctioning in of the alignment of the existing freight loop just before the station footbridge. 
All freight services could then cross over without any interference or conflict with the passenger workings and no need for the present shuffle of Richlands services from the subs to the mains then back to the subs.

[somebody]

Interesting suggestion about the flyover/under near Corinda, keeping coalies on the mains.  Doesn't really allow for freight to co-exist with express trains on those tracks IMO, but perhaps you don't need to.

Regarding grades, how steep are we talking?  Electric pax trains have pretty significant grade climbing abilities.  Even CityRail can handle the 1:30 out of Wynyard toward the Harbour Bridge with 1.5kV electrification.

[ozbob]

I don't see how there would be an issue with "not enough room" for the fly-under from Richlands to the old Darra platform #3?  Have a look at the old setup, still visible in Google Earth.

I am presently at Darra.  No, there isn't enough room.  I have watched Darra almost daily for 3 years, there were better options.

The real issue is the 4th line and the arrangements at Corinda.  The Corinda flyover idea was part of the initial plan, but killed off up high.

[O_128]

Possibly, but not enough room.

I would have just kept the quad going straight through, no freight loop.  Richlands branch just goes up from the subs.

The advantage of the islands is the shared ammenties as well for pax.  The only platform with anything on it is platform 4 now.  No water toilets etc. on the other three platforms.

If you wanted to streamline transfers and so forth crossings can be easily laid.  The advantage of this is simple and avoids the criss crossing if the up sub is electrified and so forth.  Will still be achieved eventually, but if they chose to do this layout the money saved on the freight loop would have paid for the full electrification from day one ...

Or they could have really done it properly and built a proper concourse above or below.

[somebody]

I'm still confused.  There was previously a track and platform on the north side of the current "down main".  Where exactly is there "not enough room"?  I am assuming that the gravel road for track maintenance etc would be relocated to the south side of the line.

I'm thinking like this:


                /----------\
               /   Platform   \
---------)/(----------------------------------------Down Main
            /                   \
------)/(-------------------------------------------Up Main
        /     /    Platform
----)/(---------------------------------------------Down Suburban
      /     /
From Richlands

Doing so would also have allowed for a 5th road through Darra for freight, although conflicting with Richlands bound services and Ipswich->Port trains still conflict with Ipswich bound trains without another flyover.

[mufreight]

The use of the mains for freight with the flyover at Corinda was killed off because of the cost of constructing the flyover but was the preferable option in terms of operation.
The justification was that when (read if) the southern freight bypass between Ebenezer and Kagaru is built there would be minimal freight traffic east of Ebenezer on the Ipswich line.
There is not enough room at Darra through the station area for a fifth line and not enough length to the west of platforms at Darra for a flyover to the mains from the Richlands line being constrained as it is by the Centenary Highway, Warrender Road and the road connections between the Centenary Highway and the Ipswich Motorway.
There are as a consequence of the beancounters design a number of problems that will require more costly solutions when as it inevitably must there is an amplification of the tracks between Darra and Redbank.

[somebody]

There are as a consequence of the beancounters design a number of problems that will require more costly solutions when as it inevitably must there is an amplification of the tracks between Darra and Redbank.

I am sorry, but I see that one as yet another example of a concrete fetish, and doing "less with more".  Or at least the same with more.  With appropriate timings, there could be a portion of the trains from Ipswich even more express than the 6 June timetable, as I have previously detailed.

I'm still confused about where there isn't room at Darra.

[colinw]

Looking at the old layout of Darra I find it hard to understand why a dual island platform arrangement was not retained, but then what would I know?  :conf There was clearly enough room for 5 tracks with two island platforms and a freight loop.

In comparison, while the current Darra layout doesn't accomodate a 5th track track, it is possible to see that the rail corridor is wide enough to squeeze one through to north of the station. It would require expensive changes to the just completed station access from Manburgh Tce.  If this were done, you would actually end up with a 5th platform at Darra.  There is a good 8 metres between the platform & Manburgh Tce, surely enough room for another track.

Too late now, yet another botched infrastructure delivery which achieves a suboptimal end result.

[ozbob]

On the mark Colin,  meanwhile a few photographs down from Darra ..

Note empty grain on the main up, and the Westlander heading back from the wild west on a Saturday morning!













Photographs R Dow 7th May 2011

[ozbob]

@Simon

The problem is the amount of space available in the linear direction.  These two photographs show the branch joining the subs.  The points are about 4 carriage lengths from the end of the platform.  There simply wasn't the room to take the down branch under and back up and achieve the platform.





Photographs R Dow 8th May 2011

[somebody]

But I was saying to put the inbound line onto the other side of the up/down mains.

Isn't it clear in my ascii art?

[ozbob]

I thought the diagram was just what is now.

Platform 4 is the main down, platform 3 main up platform 2 is the sub down (and where the branch down comes through), platform one is the up sub which is either the loop or up branch.  I think I am missing what you mean? 

Are still suggesting a fly-under?  Still be the same issue of getting up in time ..

[somebody]

I thought the diagram was just what is now.

Platform 4 is the main down, platform 3 main up platform 2 is the sub down (and where the branch down comes through), platform one is the up sub which is either the loop or up branch.  I think I am missing what you mean? 

Are still suggesting a fly-under?  Still be the same issue of getting up in time ..

Yes, still thinking about a fly-under.  Would be an issue of getting up in time, but I can't see that a 1:30 grade in what would be a braking area for the train anyway would be a problem.  So, maybe not the biggest deal.

                /----------\
               /   Platform   \
---------)/(----------------------------------------Down Main
            /                   \
------)/(-------------------------------------------Up Main
        /     /    Platform
----)/(---------------------------------------------Down Suburban
      /     /
From Richlands

What is there now would be:

                   Platform
----------------------------------------------------Down Main
                                      /
----------------------------------------------------Up Main
                   Platform   /        /
----------------------------------------------------Down Suburban
           /                       /
------)/(----------------/
        /      /  Platform
       /      /
From Richlands

Or something like that.

Only showing electrified tracks.

[ozbob]

Ok, see it now.

I think just running the quad straight through with the branch peeling off the subs and up over Warrender with the two island platforms would have been fine.  Clearly the 4th line electrified and continuous with the subs at Corinda would eliminate the crosses with the down sub services and the freighters would just slot in seamlessly.  This would be dependent on the 4th platform at Oxley being built as well.  Money saved at Darra would have covered that, and avoids the costly expenditure down the track to come back and do it in any case.

It is odd that the freighters are still going on the mains.  The 'freight' line is left with nothing on it.

[somebody]

Annecdotal evidence is that while the track layout works OK for passenger, it's not so good for freight.

I think the major lack is the lack of a crossover from the "down main" to the "up main", which would allow down freight to refuge between Darra and Corinda before needing to conflict with the O/B trains to reach Tennyson.  I don't really see the need for expensive flyovers here.

[petey3801]

Annecdotal evidence is that while the track layout works OK for passenger, it's not so good for freight.

I think the major lack is the lack of a crossover from the "down main" to the "up main", which would allow down freight to refuge between Darra and Corinda before needing to conflict with the O/B trains to reach Tennyson.  I don't really see the need for expensive flyovers here.

There is a crossover from the Down Main to the Up Main on the Ipswich side of Darra..

[somebody]

Annecdotal evidence is that while the track layout works OK for passenger, it's not so good for freight.

I think the major lack is the lack of a crossover from the "down main" to the "up main", which would allow down freight to refuge between Darra and Corinda before needing to conflict with the O/B trains to reach Tennyson.  I don't really see the need for expensive flyovers here.

There is a crossover from the Down Main to the Up Main on the Ipswich side of Darra..

The problem with that crossover is that it has conflicts with "up" trains towards Ipswich, pax and freight.  If there was a crossover west of the loop line's junction, these conflicts wouldn't exist.

[somebody]

Here is a sketch map of the track layout presently at Corinda

Hold on a minute, why isn't the up main connected to the down sub here, without conflicting with either the down main or up sub?

I guess you could equally ask the question: why isn't there a reverse crossover at Panhard St (Darra) between the up main and down main i.e. inbound from the down main to up main.

EDIT: Actually, that crossover would be better located west of Darra, but east of where the track joins up from Darra #1.  A 1500m train would be able to refuge on the up main and not block pax trains, then pass the Panhard St crossovers, refuge again before crossing the up trains (only) at Corinda.  Current situation is that they also need to cross the down trains from Richlands and cannot wait too long as a down train from Ipswich won't be too far away.