In the 1980s many of Melbourne’s public transport bureaucrats and managers became fixated with ‘light rail’ (a high-falutin word for ‘tram’) as a replacement for traditional ‘heavy’ rail systems. Light-rail enthusiasts scored an early victory in 1988 when the St Kilda and Port Melbourne train lines were closed and converted to tramways, with the result that a quarter of a century later, people are being sardined onto overcrowded trams, or being left behind altogether. The idea still resurfaces from time to time, either of replacing existing train lines with light rail, or (more commonly) building a tram line where a heavy rail ‘backbone’ is warranted, on the pretext that doing so would be much cheaper.
The experience with the St Kilda line is an object lesson in how substituting a tram line for a train line cripples its capacity. While a tram service can run at around three times the frequency of a train service (largely by running at lower speed), a train can carry ten times as many passengers as a single ‘light rail’ vehicle. This means firstly, that the overall capacity of a light rail line is only around one-third that of a heavy rail line, and secondly, that cost savings in building a light rail line instead of a heavy rail line are largely cancelled out by the need to buy more vehicles (and hire more drivers) to carry the same number of passengers. So while trams are ideal for providing service in a single narrow corridor, public transport service on the whole-suburb scale requires a heavy rail backbone.
Nor is it necessarily true that the construction costs of a light rail line are less than for a heavy rail line in the same corridor. In 2020 the Eno Center for Transportation in the US compiled a comprehensive database of American heavy and light rail case studies, which confirmed first, that construction costs for any rail project are far higher in the US than for equivalent projects in Europe (a finding also applicable to Australia), but also that cost differences between heavy and light rail projects are largely due to most light rail lines running at-grade, while heavy rail lines tended to be grade separated, either in tunnels or on viaducts. When light rail projects are built in grade separated corridors, the costs are similar to those for heavy rail lines.
Defining the mode of a transit project—whether it’s light rail or heavy rail—does not correlate well with its construction cost. Most of the construction and planning inputs for both modes are the same. A transit line, whether heavy or light, includes laying track, installing electrical systems, and building accessible stations. The main difference between the two modes is that light rail tends to be mostly at-grade, and heavy rail is often either tunneled or elevated.
—Eno Center for Transportation, Five Takeaways from Eno’s Transit Capital Construction Database, 2020
Thus, when Professor Bill Russell did the first major feasibility study for a rail line to East Doncaster in 1990, the costings for heavy rail and light rail came out almost equal: $250 million for heavy rail versus $242 million for light rail. Costings have since gone up with inflation, but nothing has happened that would alter the relative figures. Given this, one would think that to get the most bang-per-buck, the government would insist on heavy rail rather than light rail for a future Doncaster line. Yet the Northern Central City Corridor Study released in 2003 not only said nothing about the heavy rail option, but recommended only a ‘feasibility study’ into a light rail line. (After a sustained community campaign, a heavy rail option was belatedly considered in a 2011 study only to be weighed down with unfavourable assumptions.)
Like Doncaster, Rowville is a well-established postwar suburb with no rail services whatsoever. A rail extension along the Wellington Road alignment from Huntingdale to Rowville would provide a much-needed high-capacity backbone to support expanded bus services throughout the Rowville, Scoresby, Mulgrave and Endeavour Hills region. It would also provide a vital service to Monash University, one of the largest single trip generators in the south-eastern suburbs with a commuter population exceeding 20,000. Yet again, prior to 2010 all the bureaucrats were prepared to propose was a
possible network option of a tram line from Huntingdale to Monash University. This would likely have cost more than a train line with the same capacity, due to the need to establish depot and other facilities remote from the existing tram network.
Enthusiasm for light rail doesn’t end with proposed new lines: even before the Rowville or Doncaster lines were on the agenda, and despite the problems that have resulted on the St Kilda line, government bureaucrats in the 1990s had no shortage of plans to replace existing rail lines with the inferior light rail alternative. The Upfield line was slated for closure in the early 1990s, before the government was convinced to save it and upgrade it instead. And of course the Alamein line, which comes under threat every twenty years or so, is also a popular target of light rail enthusiasts.
How does one explain this counterproductive light rail fetish? In part it may just be the perception of newness: ‘heavy rail’ conjures up an image of clunky 19th-century steam trains, while ‘light rail’ has modern, shiny, up-to-date connotations. One might expect this attitude from naive non-experts, but would expect high-level planners to weigh up the actual evidence for or against alternative technologies rather than just follow fashion. The less charitable explanation is that our planners do not want a high-capacity system, because they secretly believe public transport is doomed. This would be consistent with their refusal to consider new suburban rail extensions (despite pouring generous funds into roads year after year) and with their overall defeatist attitude toward attracting new public transport patrons.
Melbourne is fortunate to have inherited one of the largest train networks for a city of its size anywhere in the world. To complete this network requires only a few extensions, costing less than a modest urban freeway. ‘Light rail’ is unlikely to save much money and would cripple the potential of new lines to move large populations in the areas they serve.
Last modified: 29 December 2020