Proposed elevated rail line and station at Noble Park
Proposed rail line and station at Noble Park showing open space “created” by elevating existing tracks to eliminate a level crossing

The Andrews Government announced on the weekend it plans to spend $1.6 billion to build 8.2 km of elevated track and five new stations in order to eliminate nine level crossings on the Cranbourne-Pakenham rail line (see No more level crossings between Dandenong and the city).

This is a different approach; other projects already under construction put the rail line under the road. Many residents along the Dandenong line aren’t happy with the Government’s solution, fearing noise, visual intrusion and (seriously!) the prospect of derailed trains toppling off the viaduct onto their properties (see $1.6 billion elevated rail project to replace level crossings on Dandenong line).

Elevated rail is hardly new. Think Clifton Hill to West Richmond in Melbourne, the Eastern suburbs line through Woolloomooloo in Sydney, and all those “els” in the US like the High Line in Manhattan. Of course elevated motorways are ubiquitous.

One thing this exercise tells us straight off is that it’s costing $180 million on average to eliminate each of these level crossings, even though they’re reasonably close and are being done as a package. That’s a lot of money but it’s consistent with what larger crossing eliminations are known to cost.

Another way of looking at it is that it apparently costs a surprisingly low $1.6 billion to build 8.2 km of elevated rail – including five architecturally interesting stations – over an operating rail line.

What are the alleged advantages of building rail lines “in structure”?

  • They usually cost a lot less than putting rail under the road. In this case, the crossings cluster in three groups so elevating the rail line in three sections is a logical approach.
  • It removes a longstanding barrier dividing communities and opens up opportunities for pedestrian paths and roads to be connected.
  • It “creates” land at ground level – in this case a claimed 22.5 hectares – that can be used for other purposes. The Premier is spruiking “parks, playgrounds, netball courts and thousands of new car parks”.
  • The Government says this approach causes less disruption during construction to both passengers and motorists than trenching.

As with everything, there are alleged downsides too (1):

  • Visual intrusion, overshadowing, overlooking – the viaduct and stations will be up to nine metres high.
  • Noise emanating from an elevated position isn’t attenuated by buildings and trees; it’s louder at the same distance and carries further.
  • It’s harder for passengers to access elevated stations.
  • It will be harder to expand the line as rail traffic increases e.g. from two tracks each way to four or six.
  • There will be pressure to connect dead-end streets, facilitating rat-running and greater car use.

Most of the negatives can be addressed or are exaggerated. Nine metres is the typical maximum height of dwellings in residential areas.

A viaduct can be widened to accommodate additional tracks and stations can be designed in anticipation of more tracks being provided in future.

Stations already have pedestrian overpasses and underpasses, mostly stairs. New stations can incorporate stairs, ramps, escalators and lifts.

The Government claims noise and over-looking can be handled by careful design, presumably some sort of wall; it claims the elevated sections will be less noisy than the existing line.

In terms of benefits, the “dividing communities” argument is pretty lame. This rail line dates from the nineteenth century; suburban communities have developed on either side and adapted to the existing barrier.

There are however some outstanding issues with the proposal that the Government needs to explain better to the public:

  • A mere $1.6 billion for 8.2 km of elevated rail is outstanding value compared to other recent rail projects but is it too good to be true? Perhaps this is the post-resources boom dividend but more information is needed on what’s included in the estimate and what isn’t.
  • How much will elevating the line save compared to trenching (or road under/over)? What in other words are the upsides/downsides of elevation costing?
  • How will future expansion of the line – from two tracks to four – be accommodated? The renders of the stations don’t seem to show provision for expansion.
  • Will the noise and overlooking issues be solved? How? The Government says there’ll be walls but that isn’t obvious from the video.
  • How much effort was put into investigating the option of putting the road over/under rail? How does that approach compare with elevated rail?
  • Is a “linear park” the best use for the 22.5 hectares?

The 22.5 hectares of “created” land is of particular interest as the Government realises it’s the key attribute that differentiates and justifies elevation over other options. The Premier’s media release and the renders prepared by the Government emphasise its recreational potential.

I appreciate something benign like a park is important for selling the chosen solution to residents, but it would be unfortunate if political considerations resulted in all or most of the land being effectively committed for open space at this early stage.

More parkland would of course be nice but it’s not the most serious deficiency in this area. It’s mostly suburbia where the dominant detached house and town house dwelling types have private open space at ground level as a matter of course; and where there are plenty of wide and relatively quiet streets.

Melburnians already have access to a lot of open space compared to residents of other great world cities. It’s one of the reasons Australian cities sprawl so much (see Should we deck over motorways to provide more urban parkland?).

Sure, there’s an argument that too much open space is never enough, but there are other possible uses for this land too, like commercial services, community facilities, education, transport, even housing.

For example, there’s an opportunity to use some of the land to establish well-designed multimodal interchanges at the rail stations in order to tie the rail network into a “grid” of frequent bus services (see How can public transport work better in cities?). Some observers argue elevated rail stations provide an opportunity for suburban place making.

I think it’s important at this early stage to leave open how the land could be used best for local residents and for the city as a whole. It would be sensible to focus on the quality of open space that might be provided rather than the quantity.

I like the idea of building infrastructure in structure as an alternative to the usually more expensive option of putting it below ground level. Although it seems the Government hasn’t handled the pubic consultation as well as it might have, this proposal looks promising at first glance.

The Government needs to come down to earth; it needs to convince potential supporters by substantiating its claims.

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  1. I’ll ignore derailments and pedophiles!