Fast Facts: dual-gauge railway tracks
1. The distance between the two rails of a railway track is called its gauge.
2. Most trains can only run on a track where the gauge exactly matches the width of its wheelset.
3. Australia’s mostly single-track rail network uses many gauges, so trains have to stop when they reach track with a gauge that doesn’t match its wheelset.
4. One way to extend the range of trains is to build one railway line that has two gauges. This is called a dual-gauge track.
5. Dual-gauge track usually consists of three rails – one ‘common’ rail and two rails that are closer together and accommodate for two different wheelset widths.
6. Some of the Inland Rail track is designed to be dual gauge, including the NSW/Qld Border to Gowrie section.
Rail gauges in Australia
In a perfect world, all train track gauges would be the same and so any train would be able to run on any railway track. But, in Australia, this is not the case.
That’s because our nation’s railways were constructed at different points in our history.
Each line was built to suit their location, business requirements, state government standards, technological capabilities, available locomotives and transportation needs that applied at the time they were built.
The result is that Australia’s railways do not all have the same rail gauge.
There are three main gauges used across Australia’s 33,000kms of operational heavy railways:
- The rail gauge used for most of Queensland’s tracks is called ‘narrow gauge’, which is just over one metre wide.
- But, the majority of New South Wales’s track is wider, called ‘standard gauge’, which is just over 1.4m wide.
- Victoria’s rail network is a mix of ‘standard gauge’ and ‘broad gauge’, which is 1.6m wide.
Australian rail gauges: widths and use
| Gauge name | Width between rails |
% of network |
|---|---|---|
| Narrow Gauge | 1,067mm | 36% |
| Standard Gauge | 1,435mm | 55% |
| Broad Gauge | 1,600mm | 8% |
Source: Trainline 10, Australian Bureau of Infrastructure and Transport Research Economics
Why does track gauge matter?
Trains have metal wheels that are set a certain distance apart by a fixed metal bar (axle). Together, the wheels and axle are called a wheelset. Typically, the rail line’s gauge needs to match that wheelset width for a train to be able to run on the track*.
Trains need to stop when they reach a section of track that has a different width, or gauge, to their wheelset. Cargo or passengers must be transferred onto another train or other form of transport for the journey to continue, which adds time and expense to the trip.
Where different gauged train lines meet is called a ‘break of gauge’.
Variable gauge trains:
*Another way for different gauge train tracks to be bridged is by the use of a ‘variable gauge axles’ on trains. These are specially designed trains that can adjust their wheelset width to match the track gauge.
What is dual gauge railway track and why is it used?
To allow trains to operate across two different track gauges, and to prevent a ‘break of gauge’, a third rail is added to the track.
This is called a ‘dual gauge’ railway.
This third rail allows, for example, a train with a standard-gauge wheelset and a train with a narrow-gauge wheelset to run on the same line.
This animated model shows how dual-gauge railway tracks work.
Will Inland Rail be dual gauge?
Part of the Inland Rail track is designed to be dual gauge.
There are sections of Inland Rail that will be dual-gauge track.
Inland Rail will provide a consistent standard-gauge connection from Melbourne to Brisbane as well as a dual-gauge connection in Queensland, to allow seamless connectivity with Queensland’s narrow-gauge network.
Inland Rail complements existing freight transport infrastructure by providing a consistent track standard which enables freight operators to use the same rolling-stock (locomotives, carriages, wagons or other vehicles used on a railway) anywhere on the national rail freight network.
The selected Inland Rail route uses 60% existing corridor and connects to existing regional rail lines. This connection with existing rail networks is fundamental to supporting Inland Rail’s delivery of regional economic benefits.
