QR is currently replacing two timber bridges between Ayr and Townsville. Killymoon Creek, south of Nome, is being built on a short deviation between the existing trestle and the highway, while Sheep Station Creek south of Pioneer appears to be being built under the existing structure (which was damaged by a grass fire last year). These are among the last timber trestles between Bowen and Townsville, with only three remaining when this work is finished.

Thanks as always Sulla.   Are these works part of the North Coast Rail Upgrade report that you kindly referred us to which recommended a program of further upgradings including replacement of timber bridges or are these simply that the bridges are are now life expired.  In other words are these ad hocs or is there an ongoing program.

Cheers

TP

QR has had a pretty intensive timber trestle program underway for about twelve months. In the 2015 state budget QR received $75-million for a bridge renewal and replacement program. To date most of the work has been focused on the Central Line west of Emerald and the Clermont branch. The Western Line has had a significant bridge replaced at Oakey and there's a few more big trestles on that line about to be replaced. As for the North Coast Line, at least one was replaced last year south of Cairns. These bridges are definitely life expired, but there hasn't been much of a rush to replace the few remaining timber trestles on the North Coast Line until now (possibly because they'd already been strengthened for 20-tonne axle loads).

The Western Line has had a significant bridge replaced at Oakey and there's a few more big trestles on that line about to be replaced.

Many small structures on the western line have been replaced in recent times too. Timber is getting rarer...

QR has had a pretty intensive timber trestle program underway for about twelve months. In the 2015 state budget QR received $75-million for a bridge renewal and replacement program. To date most of the work has been focused on the Central Line west of Emerald and the Clermont branch. The Western Line has had a significant bridge replaced at Oakey and there's a few more big trestles on that line about to be replaced. As for the North Coast Line, at least one was replaced last year south of Cairns. These bridges are definitely life expired, but there hasn't been much of a rush to replace the few remaining timber trestles on the North Coast Line until now (possibly because they'd already been strengthened for 20-tonne axle loads).

Back in the 1990s when the North Coast Line was upgraded to 20 ton axle load the scope of the project was to replace all timber bridges and replace all curves less than 80km/h where possible.
The standard was for 120km/h alignments where possible.
However due to changes forced on us by politicians the budget exceeded the original estimate.
The majority of timber bridge replacements were those that were on straight track with reasonable vertical alignment.
Those in areas of substandard horizontal alignment were to be replaced in the future.
Then some brilliant project manager worked out the costs of just replacing these bridges without only a small allocation of funds for deviations.
So we now have bridges being replaced "online" without any improvement to the horizontal alignment.
In some cases retaining the 50 and 60 km/h curvature of the existing alignment.
All this on a line where the allowable top speed for freight trains is 100km/h.
Both Killymoon and Sheep Station Creek ate close to low speed curves and I would be surprised if any improvement in horizontal alignment is proposed.
Building a new bridge in these areas would preclude any future speed improvement.
Queensland Transport who is the final authority for these things would not contemplate this sort of expenditure on the Bruce Highway.

At least one timber bridge I know of 70km north of Rocky was replaced in the mid 2000's and at the same time the "S" bend in the track to enable the old bridge to be perpendicular  to the river and hence as short as possible was removed and the line effectively "straight railed" across the river on the new bridge. In this case it made building the new bridge easy as the new bridge was off-set from the old bridge. Once complete, tracks are laid and a shutdown to tie in the new bridge at both sides.

It will be interesting to see what the new speed limits will be at Killymoon...the new alignment is being built on the inside of a 60km/h (right at the end of a long 100km/h section from the north). It would seem difficult to me for the new curve to be any faster than the old curve...maybe it will have longer easements and more super elevation?

Killymoon Creek



Sheep Station Creek

here's one they did north of Glenn Geddings (Sorry not sure how to get the map picture)

https://www.google.ae/maps/place/Kunwarara+QLD+4702,+Australia/@-22.9972864,150.2419388,747m/data=!3m1!1e3!4m2!3m1!1s0x6bc34421ac9e625d:0x400eef17f208490?hl=en

and another south which also included curve easing

https://www.google.ae/maps/place/Kunwarara+QLD+4702,+Australia/@-23.0383072,150.2630484,741m/data=!3m1!1e3!4m2!3m1!1s0x6bc34421ac9e625d:0x400eef17f208490?hl=en

It will be interesting to see what the new speed limits will be at Killymoon...the new alignment is being built on the inside of a 60km/h (right at the end of a long 100km/h section from the north). It would seem difficult to me for the new curve to be any faster than the old curve...maybe it will have longer easements and more super elevation?

The application of longer easements, commonly known as transitions, to an curve where the cant applied is already at the maximum allowed can not allow for an increase in speed.
Equilibrium cant is determined by riding comfort for passengers and stability of loads for freight trains.
Tilt trains can traverse curve at speeds 25% greater that normal trains by tilting to allow for the cant deficiency for the higher speeds.
An interesting bit of trivia is that 7% cant is the maximum usually applied for both rail and road.

Some fun facts I found

Max for
- USA is 3 inch, but some locations 4"
- EU is 6". 7" when no freights allowed but up to 11" (wow)

here's one they did north of Glenn Geddings (Sorry not sure how to get the map picture)

https://www.google.ae/maps/place/Kunwarara+QLD+4702,+Australia/@-22.9972864,150.2419388,747m/data=!3m1!1e3!4m2!3m1!1s0x6bc34421ac9e625d:0x400eef17f208490?hl=en

and another south which also included curve easing

https://www.google.ae/maps/place/Kunwarara+QLD+4702,+Australia/@-23.0383072,150.2630484,741m/data=!3m1!1e3!4m2!3m1!1s0x6bc34421ac9e625d:0x400eef17f208490?hl=en

RTT
These were replace in an era when sanity prevailed and improvement to horizontal curvature was considered as desirable.
Now the bean counters who have no idea as to how curves with maximum speeds of 50 and 60 km/h can affect the economics of freight train operations which can travel at 100km/h on those sections of the North Coast Line where allowable.
This from pretend "economist" who do not see the full picture.
Especially when it is Government policy to facilitate "more efficient" operations on this route which is designated a "National Corridor"

Some fun facts I found

Max for
- USA is 3 inch, but some locations 4"
- EU is 6". 7" when no freights allowed but up to 11" (wow)

These are for standard gauge tracks. Allowable cant is a function of gauge.
USA 4 inch =100mm = 7% of 1435mm.
Back to the old standard of 7%.
The maximum European values would be in areas of high speed travel.

After a just over a month of earthworks and site preparation the North Coast Line has been closed until tomorrow to cut in the new Killymoon Creek Bridge and about 1km of new track. When I drove past the site a week ago, no track had been laid and the piers weren't in place...apparently things happened very quickly over the last seven days.

It will be interesting to see what the new speed limits will be at Killymoon...the new alignment is being built on the inside of a 60km/h (right at the end of a long 100km/h section from the north). It would seem difficult to me for the new curve to be any faster than the old curve...maybe it will have longer easements and more super elevation?

The speed limit over Killymoon Creek is currently 90km/hr. There is a 60km/hr curve that starts just before the AIMS level crossing.

edit: The 60 curve can been seen on Google maps in Sulla's post above just before Clevedon? station.

Out of interest, what is the cost of a standard NG sleeper (timber and concrete variants) and what would be the cost of a dual gauge (NG/SG) sleeper (again, timber and concrete variants)?