Primer: Gauge

Australia uses mostly 1067mm Narrow Gauge, 1435mm Standard Gauge, and 1600mm Broad Gauge. (Source)

The issue of gauge is quite an important one in Australia, but because of its technical nature it tends to be overlooked by laypeople. The first thing you need to know is some basic terminology.

In standard usage, "gauge" on its own refers to how far apart the tracks are on a railway line, and therefore how far apart the wheels of the trains have to be. Because of the reliance on gauge, railways are less automatically compatible than roads, so you often have situations where two lines will meet but trains can't go from one to the other. This incompatibility is the reason gauge is so important in Australia - our network is a mixture of Standard Gauge, Broad Gauge and Narrow Gauge.

By contrast, "loading gauge" "structure gauge" and "axle load" dictate how long, tall, wide and heavy the trains on a particular line can be. This one is not such a big issue. The most pertinent difference at the moment is the height restrictions - much of NSW's network allows double-stacked containers on their freight trains, whereas Victoria's does not. It has been the policy for a few years now that any time new bridge works are done in Victoria on a line that is likely to carry freight, it should be done with enough clearance to allow double-stacked containers - but this policy is quite new, it may not have been strictly adhered to, and there is nothing being done to convert existing bridges. So there's a long way to go.

While "Standard Gauge" is pretty universally recognised to mean the 1435mm gauge which was originally picked by rail pioneer George Stephenson, and which now comprises 60% of the world's rail network, "Broad Gauge" and "Narrow Gauge" are much more ambiguous terms.

Essentially, any gauge narrower than Standard is a "narrow gauge" railway, and any gauge broader than Standard is "broad gauge". There are a great many gauges throughout the world that use these names as shorthand, but unless otherwise specified, in this article and the blog at large:
- "Broad Gauge" is 1600m Irish Gauge, and is used in Victoria and South Australia.
- "Narrow Gauge" is 1067mm Cape Gauge, and is used in WA, Queensland, Tasmania and South Australia.

There are several other narrow gauges in play scattered throughout the country (eg sugarcane and tourist lines) but these don't matter much for our purposes.

Dual Gauge track at Wallaroo, South Australia (Source)

"Dual Gauge" track exists throughout Australia, where multiple gauges need to co-exist but two separate tracks can't be justified. Essentially, one rail (the rail on the left in the above photo) will be used by both kinds of trains, whereas the other two rails (on the right) will only be used by one kind.

So. How did we get here?

The story of Australia's gauge woes is an incredibly frustrating one. While most European countries followed Britain and adopted the 1435mm Standard Gauge, some chose to have a different gauge to their neighbours in order to slow down invading armies. While this was not without its economic drawbacks, it did work quite well. Also, many countries that had been colonised by European nations, particularly in South America, opted for various narrow gauges because it was a lot cheaper to build than Standard Gauge. But Australia's mix of gauges were not so much brought on by deliberate (if short-sighted) planning - they were largely brought on by a giant cock-up.

While the British Crown advised its colonies in Australia to adopt Standard Gauge, the chief engineer on the first lines in New South Wales decided to use the Broad Gauge of his native Ireland. Standard Gauge had many advantages when it came to compatibility with European locomotives, but it was more important that all the lines on the continent be the same - so Victoria and South Australia followed NSW's lead and set in place plans for Broad Gauge railways as well. However, before NSW's railways could really get started, its chief engineer was replaced by a Scottish engineer who preferred Standard Gauge; the NSW government was persuaded to change gauges, but by then it was too late - Victoria and South Australia were locked into Broad Gauge and refused to change.

Then Queensland and WA opted for Narrow Gauge railways due to their cheapness (and in the case of WA at least, because they were so far from the other colonies that they figured it didn't matter) and SA and Victoria experimented with Narrow Gauge lines for the same reason. There have been some attempts to Standardise key lines over the last century - for example, the main freight lines between the capital cities are now all Standard Gauge - but broadly speaking, we are still recovering from this mishmash of different gauges. The worst thing is, new track is still being laid in non-Standard gauges, as each state expands their rail network but can't be bothered paying for the existing bits to be converted. So in many ways, things are actually getting worse.

There is the option of laying Dual Gauge track as an intermediary step, but this can present problems of its own. Standard Gauge and Broad Gauge are so close together, that where the two are combined into Dual Gauge, speed restrictions need to be put in place to prevent derailments. By contrast, this is less of a problem in WA, because Standard and Narrow gauges are further apart.

Perth's suburban trains using Narrow Gauge alongside the Indian Pacific on Standard Gauge (Source)

Not only does it cost a lot to convert all that track, but while we remain in this limbo it costs a lot extra because we essentially need to maintain parallel fleets - one for each gauge. It results in a lot of duplication and a lot of unnecessary redundancy, but there is not much we can do beyond speeding things up in getting things Standardised. There is not a heap of political will to do that at the moment, though.

Both track and fleet complications hold back several projects that otherwise might be feasible. For example, the return of passenger trains between Ararat and Horsham would at the very least be worth looking into if it were just a matter of extending the existing Ballarat-Ararat service. However, as it stands there is a break-of-gauge at Ararat, so there is no chance of it going ahead until that changes.

While ultimately you'd like to see everywhere in the country on Standard Gauge, that may never happen. In Victoria at least, it might not really need to - ever since day one, freight, regional passenger and metro passenger trains have all shared a lot of the same tracks. However, this is becoming less and less so with time - a lot of freight is now on the Standard Gauge network, for one thing. There is also a push, as we add capacity to the network, to separate suburban and regional trains on their own tracks - the Regional Rail Link is a prime example of this. If things continue in this direction, it may be quite possible to have all freight and V/Line Passenger trains on Standard Gauge, while leaving Metro trains on Broad Gauge. Doing this would be a lot financially and politically easier than converting the Metro system as well, and would have few downsides in terms of flexibility (we already have two parallel fleets because they serve such different purposes).

How exactly this process of Standardising Victoria should go will be the topic of a future post, although it's worth noting that V/Line already runs Standard Gauge passenger trains on the Albury line, as it has recently been gauge-converted. As I said, projects like Regional Rail Link make it easier, but serious movement on passenger lines probably won't get started until more of the freight network is converted. The recently announced Murray Basin Rail Project, which is primarily done with freight in mind, is therefore going to be a big boost - once it's done, basically all of Western Victoria's freight network will be Standard Gauge, and that may well be the tipping point we need.