Join Date: Jun 2007
Likes (Received): 0
NZ | Rail + Freight
Rather than dragging the NZ Public Transport thread
further off topic, I think it's time for a new thread. News, discussion, etc of rail related stuff that doesn't fit in the PT threads.
Here is something to start it off that I recently read in the National Freight Demands Study
[pdf]. I think it provides a good overview of some of the issues. (Sorry it's rather long.)
Developments in improving the infrastructure can be grouped as follows:
5.3.3 Transit time and reliability
- transit time reliability
- load capacity (axle loads)
- line capacity
A large number of the maintenance-risk issues are managed by reducing speeds (temporary speed restrictions). As a result, required work on track, sleepers and formation and structures (bridges and tunnels) may build up as limited funds are prioritised elsewhere, and overall transit time on a particular line may then increase. Increased expenditure by ONTRACK on maintenance on key lines is reducing speed restrictions and improving transit times. Further investment in formation maintenance and bridge upgrading is planned. ONTRACK has also invested in new major, railmaintenance machinery, including 40 new ballast wagons, a „dynamic track stabiliser', a ballast cleaner and a tamper, which will increase the length of line maintained in a year and speed its return to normal traffic transit times.
Much of the country's rail network runs on its original alignment. Some routes were realigned throughout the last century (eg, in the 1930s, 1950s and 1980s) but nowhere near as much as has been done on the highway network. Many lines still suffer from speed restrictions on tight curves and steep grades. Improvements to many of these are
quite feasible, given funding. Current thinking includes improvements on the alignment of the Otaki-Manakau section, a deviation from Kakariki to Porewa to avoid the steep grades into Marton, and easing a sharp, slow-speed curve north of Taihape. Longer term, and on a larger scale, grades on the coal route between the West Coast and Canterbury at Reefton, Cass and near Springfield could be eased, as could other curves on the Taihape - Taumarunui section.
Transit time also interacts with line capacity in terms of signalling and crossing loops. Signalling on the Rolleston - Arthur's Pass route is currently planned for upgrading to centralised traffic control and motorised points, which will improve speed, capacity and safety.
A legacy of the nineteenth century construction is limited clearances, mainly through tunnels. The principal restriction is height rather than width, although height and width interact in the area of the curved roof of tight tunnels. Some usually less-used lines cannot take 9ft 6in-high containers, the modern „hi-cube' standard. Most principal lines can take these containers, albeit in some cases with limitations on the wagons that can be used, or with speed restrictions. The most important exceptions are Greymouth - Christchurch and North Auckland.
Currently, the line through the Manawatu Gorge to Napier, and the Marton-New Plymouth line are also restricted. A major project to remove the restrictive tunnel on the New Plymouth line has just been completed, and removal of the restrictive tunnels in the Manawatu Gorge will be completed this year.
On the Auckland-Tauranga and Invercargill-Port Chalmers routes, even higher containers, up to 10ft (3.05m), are allowed. These are special containers for internal use only, as they are also too large for export use. They are used mainly for dairy products as their size permits double stacking of product on pallets, and thus greater
efficiency. Double-stacking of standard pallet sizes is not possible in a 9ft 6in international container, a problem overcome for that journey by using slipsheets. Further work to extend the use of 3.05m containers throughout the network is feasible but is not currently planned.
In the longer term, clearances on the North Auckland line would need to be improved if Marsden Point becomes a major container port, but would require significant expenditure on a replacement for the Makarau tunnel, and as much again to improve many of the other 12 tunnels on the route between Auckland and Whangarei.
There are also plans to remove the first tunnel on the Rolleston - Arthur's Pass route, which is part of the Midland Line between Christchurch and the West Coast. This will improve speeds over that section but, because there are other restrictive tunnels further west, it will not improve clearances on the route as a whole.
5.3.5 Load capacity
Most of the network is capable of carrying 18-tonne axle loads. A 6-axle locomotive can therefore weigh a maximum of 108 tonnes and a 4-axle wagon a maximum of 72 tonnes. The most efficiently constructed wagon on the system at present has a tare weight of 15.5 tonnes, which means that it can carry 56.5 tonnes of freight (including containers).
Modern diesel-electric locomotives including most locomotives built for New Zealand's 1067mm gauge, weigh much more than 108 tonnes. Examples include Queensland's newest diesel-electrics at 119 and 120 tonnes. Given that the hauling power of a locomotive is at least partly related to the weight available for adhesion, an 18-tonne axle load is a limiting factor.
A target for the New Zealand rail network is therefore a 25-tonne axle load, a 39 percent increase on the 18-tonne load.
Both track and bridges are impacted by axle loads, and current track and bridges limit the ability to improve beyond 18 tonnes. It costs relatively little to design and build bridges for heavier loads, so code reviews are currently taking place so that new bridges will be built to carry 25-tonne axle loads. For some years, track has been built for a 22.5-tonne capability. But many bridges and much track remain from times before these standards were introduced, so a focused investment plan for a particular route is necessary before more than 18 tonnes is allowed. Bridges are the critical issue. An accelerated programme to replace the 2,900 wooden piers (521 bridges) is underway and 562m of bridge were replaced or upgraded in 2006-07.
Much of what is carried on New Zealand's rail and road networks is not dense enough to use more than 18-tonne axle loads and relatively few commodities would benefit from heavier axle loads. These include steel, coal, limestone, cement and bulk liquids such as wine in containers. International containers of some exports, such as some dairy
products, may also benefit. Import containers are usually lighter. Note though, that the trend to using 40-ft containers limits the usefulness of higher axle loads – the weight in a 40-ft container is limited by the structural strength of the container and the lifting capability of wharf cranes, which is usually less than 40 tonnes. This is well within the current 18-tonne axle load. Twenty-foot containers could well weigh in excess of 18.8 tonnes each; the practical limit for three of them on a wagon with an 18-tonne axle load. If 20-ft containers continue to be in common use, heavier axle loads may be beneficial.
KiwiRail is buying 100 new container wagons, mainly for Metroport traffic between Tauranga and Auckland. These are capable of an 80-tonne gross weight or 20-tonne axle load. With the tare weight of the wagon subtracted, it can carry nearly 62 tonnes of freight or three 20.5-tonne, 20-ft containers. Some older wagons could also have bogies
upgraded to 20-tonne axle load. These are both interim solutions, and further new container wagons could carry up to 65-tonne loads, still with a 20-tonne axle load. ONTRACK is actively looking at improving the Auckland-Hamilton line to carry 20-tonne axle loads as an early step on the way to 22.5 tonnes. Hamilton-Tauranga will be the next to follow.
Extending this to other routes would require significant expenditure.
5.3.6 Line capacity
Double-track sections of track have very high capacity in terms of the number of trains, depending on signal spacing. The main double-tracked routes outside suburban passenger areas are Papakura-Hamilton (90 km) and Heathcote-Islington in Christchurch (18km). The effective capacity of the Papakura-Hamilton line is limited by two singletracked sections (13km) from Auckland to Te Kauwhata and across the Waikato river at Ngaruawahia between Huntly and Hamilton. At present, they pose no real restriction on capacity.
Double track is being extended in West Auckland and Wellington, primarily for passenger trains. The freight network outside these routes is single tracked. The capacity of single-track routes is influenced by the number and length of crossing (passing) loops, and signalling systems. In much of the country these are appropriate to the traffic
demands on them. Most routes have relatively low-density traffic in terms of number of trains that are run.
When traffic is denser, lines can reach capacity constraints. On the Hamilton-Tauranga route the extension of crossing loops to 900 metres long and the construction of two new crossing loops, is underway at a cost of about $10 million. With the extension of a further loop east of the Kaimai tunnel, this expenditure will double the capacity of the line.
Replacing the signalling on the Midland line between Christchurch and the West Coast, noted above, will also increase the capacity of that line. Further improvements to crossing loops would benefit the North Island Main Trunk line (NIMT) in the central North Island and between Palmerston North and Waikanae.
5.3.7 Line extensions
The rail freight network reaches all significant parts of New Zealand, except Nelson. It also reaches all ports except Nelson and Marsden Point. A line is planned to connect Marsden Point to the network and work is underway to designate the route.
Further short extensions are likely to connect particular industrial plants directly to the network. The three currently under consideration are to a proposed cement works at Weston, near Oamaru (under action for designation), to a coal-loading facility (to be built this year) at Ikamatua, and a line to the dairy plant at Clandeboye.
The Onehunga branch is being reopened for passenger use. Part of the Rotorua branch near Putaruru is being reopened to serve a water-bottling plant. The remainder of the Rotorua branch may be reopened for passenger use if local plans to run passenger trains come to fruition.
While a number of parts of the network carry very light traffic, there are no current plans to close any of them.
Rail use is hampered by a lack of wagons and locomotives. As noted above, new container wagons have been purchased and a number of moth-balled wagons have been restored to service. With the return of rail freight to the government, the purchase of further new wagons is now being planned.
At present, there is heavy demand on the locomotive fleet at certain times of the year and the needs of freight have to compete with the growing demands for locomotives for passenger services, particularly in Auckland. Consequently, at these times there are no spare locomotives available for freight. Previously spare lower-powered locomotives have been refurbished and put into passenger service in Auckland. The purchase of new locomotives has been planned for some time, but not proceeded with because of the issues between Toll and ONTRACK. These issues have been resolved with the repurchase of the transport system, and the purchase of locomotives is now also planned. Meanwhile, some of the existing locomotive fleet has been improved, with larger engines and traction-control systems, significantly increasing the load the locomotives can haul up grades.
In recent years, container-transfer centres have been developed to expedite the movement of freight from road to rail. These are confined largely to main and secondary centres. Some expansion of this concept to other places is possible. Previous management linked the development of these sites to a reduction in direct access to industry via private sidings. This has reversed recently, but there are still issues with the availability of local train services to serve private sidings.
A similar concept ("inland ports") has been developed with the Metroport operation between Tauranga and South Auckland. The government is reported as having offered to contribute $6 million to the cost of providing rail access to the terminal, allowing the operation of shuttle trains from the port and taking heavy-vehicle traffic off the Auckland motorway network. This proposal is likely to go ahead.