The cost of Duplication

 
  potatoinmymouth Chief Commissioner

Gentlemen, gentlemen... no need for a pissing contest.

Sponsored advertisement

  DirtyBallast Chief Commissioner

Location: Standing at the limit of an endless ocean
^ It's not that at all. I simply asked BG to apply some perspective. Did you miss that bit?
  BrentonGolding Chief Commissioner

Location: Maldon Junction
Gentlemen, gentlemen... no need for a pissing contest.
potatoinmymouth
Yes, sorry, I didn't mean to take the thread off track. My original comments were in no way meant to be taken as me saying that we of the Bendigo line were any worse off than others - to say that we are long suffering is not to say that others are not in the same boat.

The thread seemed to have morphed into a discussion about the Bendi line in particular which I don't think was the OPs intent. Then someone else ascribed that meaning to my post and I responded, I should have just let it slide.

BG
  TOQ-1 Deputy Commissioner

Location: Power Trainger
To answer the origininal question :

It is cheaper to restore an existing duplication than duplicate an existing single line , because the second category requires all new earthworks, bridges, culverts, viaducts etc .

E:G:  To restore duplication between Kyneton and Bendigo one does it in stages

Stage - 1  Kyneton to Up end Taradale Loop, + Extend Castlemaine Loop to down end of Harcourt, restore double track section through Bendigo Yard.
Stage - 2  Down end Taradale Loop to Up end Castlemaine Loop +  Down end Hardcourt Loop to Up end Kangaroo Flat .
The problem that I see with doing it that way is that you are condemning long suffering Bendigo pax to multiple long term shutdowns and bustitutions. We already went through one for RFR then another for RRL now you are talking about another 2.

BG
Because Bendigonians are sooooo precious compared to Gippslanders, they're not to be further disrupted....right?
Yes the Kyneton - Castlemaine section would need shutting down for reduplication (Kyneton to Taradale) but bustitutions would be anything like what the Gippsland line has coped with during Metropolitan works.

You would have express coaches form Kyneton to Castlemaine, to Bendigo and a local bus shuttle for Malmsbury, trains should be able to work from Castlemaine to their Northern terminus (altered times to fully connect with the coach)

When It comes time to reduplicate Castlemaine to Harcourt, Trains from Melbourne terminate at Castlemaine and coaches run to Kangaroo Flat and Bendigo.

Yes some pain, but the only way to fix up the mess left by the Regional Fast Rail Project (that people of Castlemaine fiercely objected to during the planing process)
Nightfire
You probably wouldn't want an orphaned train fleet in Bendigo. Shut everything North of Kyneton first with express coaches as you say, then transition to Castlemaine being the terminus. Running what is essentially a Castlemaine to Bendigo Shuttle for most services wouldn't be worth the hassle of getting passengers to change twice.

Use the opportunity to make as many trains as possible available for Geelong and Ballarat, store any excess H sets in Bendigo for the duration if need be.
  Nightfire Minister for Railways

Location: Gippsland
You probably wouldn't want an orphaned train fleet in Bendigo. Shut everything North of Kyneton first with express coaches as you say, then transition to Castlemaine being the terminus. Running what is essentially a Castlemaine to Bendigo Shuttle for most services wouldn't be worth the hassle of getting passengers to change twice.


TOQ-1
Last time the Bendigo was line was shut down for RFR works, the Government thought they could get away with shuting down all trains In the Bendigo area, but public demand forced their arm to restore the Swan Hill Bendigo train service.

Since RFR the local ridership between Castlemaine and Bendigo has grown significantly, so give the option of a express service from Kyneton to both Castlemaine (to join the shuttle train) and Bendigo (for those who don't want an additional change)


See what option gets the most patronage.
The road journey Into Bendigo from Castlemaine Is getting slower and slower due to traffic congestion.
  BrentonGolding Chief Commissioner

Location: Maldon Junction
Last time the Bendigo was line was shut down for RFR works, the Government thought they could get away with shuting down all trains In the Bendigo area, but public demand forced their arm to restore the Swan Hill Bendigo train service.

Since RFR the local ridership between Castlemaine and Bendigo has grown significantly, so give the option of a express service from Kyneton to both Castlemaine (to join the shuttle train) and Bendigo (for those who don't want an additional change)


See what option gets the most patronage.
The road journey Into Bendigo from Castlemaine Is getting slower and slower due to traffic congestion.
Nightfire
True Nightfire but given that the consensus seems to be that work will also be done between CME and Porcupine Loop it would seem sensible to me to get enough boots on the ground to do both sections at once - yes, a lot of pain but IMHO would be far less messy than doing multiple smaller occos.

Hopefully they decide to run buses to Kyneton to join trains instead of the whole way to SC but I'm not holding my breath!

BG
  BrentonGolding Chief Commissioner

Location: Maldon Junction
The tunnel 'issue' (and the heritage rail underbridge clearance problems as well) has a readily available engineering solution. Installation of slab track (as seen on CTD/Skyrail) with related bridge/tunnel excavation works can enable up to a 600mm drop in rail head height, enabling the track centres to be widened enough to enable trains to cross at 130kph and possibly even higher speeds inside/underneath these structures. The existing TPWS signalling installed during RFR enables direct enforcement of speed restrictions around these structures if required.
LancedDendrite
The thing that I don't understand about this is that there are already "heritage structures" with 2 tracks running through them on the line. There is a bluestone road over bridge near the 111km post on the dual track Elphinstone Loop and there is at least one south of Kyneton as well.

Were these built slightly wider than the others on the line or was a solution just found for these out of necessity ie track lowered through them.

The slab track would be a great idea for the tunnels, I assume it would be super expensive but have reduced maintenance costs over the medium to long term?

BG
  historian Deputy Commissioner

The tunnel 'issue' (and the heritage rail underbridge clearance problems as well) has a readily available engineering solution. Installation of slab track (as seen on CTD/Skyrail) with related bridge/tunnel excavation works can enable up to a 600mm drop in rail head height, enabling the track centres to be widened enough to enable trains to cross at 130kph and possibly even higher speeds inside/underneath these structures. The existing TPWS signalling installed during RFR enables direct enforcement of speed restrictions around these structures if required.
The thing that I don't understand about this is that there are already "heritage structures" with 2 tracks running through them on the line. There is a bluestone road over bridge near the 111km post on the duel track Elphinstone Loop and there is at least one south of Kyneton as well.

Were these built slightly wider than the others on the line or was a solution just found for these out of necessity ie track lowered through them.

The slab track would be a great idea for the tunnels, I assume it would be super expensive but have reduced maintenance costs over the medium to long term?
BrentonGolding


There is nothing particularly miraculous about slab track; it just lowers the rail level. It is particularly useful where you need to get additional clearances above the train (i.e. for overhead electrification).

Whether or not it improves lateral clearances depends on the shape of the structure. Heritage overbridge abutments are almost always vertical, so the provision of slab track would have no effect on lateral clearances.

Heritage tunnels are egg shaped or circular (to resist the thrust of the soil, and, especially, the water it contains), so the effect is more complex. Lowering the rail level increases the clearances at the upper corners of the car bodies (cant rail). This is good as that is where the sway is greatest. On the other hand, it reduces clearances at and below the car body floor level. This is not a problem for swaying (the bogies are fixed in location by the rails and hence movement is low), but is a problem for workers in the tunnel and any equipment. Lowering the track usually doesn't allow increasing the track centres due to the curvature of the walls.

I would suspect that slab track has other advantages than just lowering the floor. It fixes the track in the transverse direction, rather than the track floating in the ballast. This itself would allow tighter tolerances. Don't forget that the track condition in a tunnel is harder to inspect and fix than in the open (or under an overbridge).

More vertical clearance can be obtained by undercutting the floor. This gets substantially more complex as you need to alter how the designers resisted the side thrust of the tunnel walls. In poor soils there is actually another arch buried under the track (the invert). In rock, the thrust is taken by the rock floor. In either case, you can't just take the mechanism away without providing a replacement. Retrofitting such a replacement is very complex engineering.
  justarider Chief Commissioner

Location: Released again, maybe for the last time??
The tunnel 'issue' (and the heritage rail underbridge clearance problems as well) has a readily available engineering solution. Installation of slab track (as seen on CTD/Skyrail) with related bridge/tunnel excavation works can enable up to a 600mm drop in rail head height, enabling the track centres to be widened enough to enable trains to cross at 130kph and possibly even higher speeds inside/underneath these structures. The existing TPWS signalling installed during RFR enables direct enforcement of speed restrictions around these structures if required.
The thing that I don't understand about this is that there are already "heritage structures" with 2 tracks running through them on the line. There is a bluestone road over bridge near the 111km post on the duel track Elphinstone Loop and there is at least one south of Kyneton as well.
.......

Whether or not it improves lateral clearances depends on the shape of the structure. Heritage overbridge abutments are almost always vertical, so the provision of slab track would have no effect on lateral clearances.

Heritage tunnels are egg shaped or circular (to resist the thrust of the soil, and, especially, the water it contains), so the effect is more complex. Lowering the rail level increases the clearances at the upper corners of the car bodies (cant rail). This is good as that is where the sway is greatest. .........

...and lots more good details....
historian
BG your point ".. already "heritage structures" with 2 tracks... a bluestone road over bridge "
misses that there is a fundamentally different dynamic about how a train passes thru a tunnel vs passes a bridge.

Historian said it "sway".

Going under a bridge, no noticable wind pressure pushing on the train.
In a tunnel it's significant, and more speed = more pressure.
You can feel it at a subway tunnel platform. In the London tubes it can nearly knock you back.

That pressure also affects the train itself, and it can sway. Usually not very noticeable but when you have 2 trains in the tunnel going head on , you better have enough clearance in case they both sway towards each other at the wrong moment.

Trains did go thru those tunnels at 130kph in the past. Frankly I'm surprised that was ever considered "safe".
Perhaps because the infrequent schedule ensured that never 2 trains in the tunnel at same time.
With the much more frequent schedule nowadays, we don't have that luxury.

Positive steps need to be taken to avert the risk,
such as 1. single track 2. stop signal 3. separate tunnels 4. bore out the tunnel to be much wider 5. a dividing wall in the tunnel
first 2 options will affect the schedule, and any late running will cascade - like it does today
the 3rd option costs a lot of money
4th & 5th option - aargh !!!

cheers
John
  BrentonGolding Chief Commissioner

Location: Maldon Junction
The tunnel 'issue' (and the heritage rail underbridge clearance problems as well) has a readily available engineering solution. Installation of slab track (as seen on CTD/Skyrail) with related bridge/tunnel excavation works can enable up to a 600mm drop in rail head height, enabling the track centres to be widened enough to enable trains to cross at 130kph and possibly even higher speeds inside/underneath these structures. The existing TPWS signalling installed during RFR enables direct enforcement of speed restrictions around these structures if required.
The thing that I don't understand about this is that there are already "heritage structures" with 2 tracks running through them on the line. There is a bluestone road over bridge near the 111km post on the duel track Elphinstone Loop and there is at least one south of Kyneton as well.
.......

Whether or not it improves lateral clearances depends on the shape of the structure. Heritage overbridge abutments are almost always vertical, so the provision of slab track would have no effect on lateral clearances.

Heritage tunnels are egg shaped or circular (to resist the thrust of the soil, and, especially, the water it contains), so the effect is more complex. Lowering the rail level increases the clearances at the upper corners of the car bodies (cant rail). This is good as that is where the sway is greatest. .........

...and lots more good details....
BG your point ".. already "heritage structures" with 2 tracks... a bluestone road over bridge "
misses that there is a fundamentally different dynamic about how a train passes thru a tunnel vs passes a bridge.

cheers
John
justarider
You have misinterpreted my post, sorry. I was talking about 2 different things, thinking that LDs Slab track solution for Tunnels sounded like a good one and also wondering why the items that he referred to as "heritage rail underbridge" are such a problem when there are already at least 2 of these with 2 active rail lines running through them on the line ATM.

BG
  awsgc24 Minister for Railways

Location: Sydney
For the approximate cost of a new double track tunnel at Frentini in Europe, about 500m long, see https://www.railpage.com.au/f-p2128899.htm#2128899 .

According to http://www.rayex.com.au/?gclid=EAIaIQobChMIxIe0xdWj3wIVUgwrCh2wHwU0EAAYASAAEgK2QfD_BwE ,

EUR25m = AUD40.2m.

The new tunnel does not need to be fully double track in size, as the existing double track tunnels (Big Hill/Elphingstone) can be retained as a single track bore.

See: http://www.rayex.com.au .
  Nightfire Minister for Railways

Location: Gippsland
For the approximate cost of a new double track tunnel at Frentini in Europe, about 500m long, see https://www.railpage.com.au/f-p2128899.htm#2128899 .

According to http://www.rayex.com.au/?gclid=EAIaIQobChMIxIe0xdWj3wIVUgwrCh2wHwU0EAAYASAAEgK2QfD_BwE ,

EUR25m = AUD40.2m.

The new tunnel does not need to be fully double track in size, as the existing double track tunnel can be retained as a single track bore.

See: http://www.rayex.com.au .
awsgc24
There are 2 perfectly good double track heritage tunnels already, use the to their full parental, like they were used for 142 years.

Single tracking like the tunnels saved 3 seconds In journey time, but wasted many minutes at crossing loops.

Sponsored advertisement

Display from:   

Quick Reply

We've disabled Quick Reply for this thread as it was last updated more than six months ago.