New rail technology: Alstom's Axonis light metro

Railways are the freeways of the public transport world. They consume enormous amounts of capital during design and construction phases and require regular maintenance once operational. Comparatively speaking, both railways and freeways allow for the fastest journeys to be made and they also have the highest scope for increasing capacity to transport people around cities in their respective purviews.

In isolation both types of transport modes will have varying degrees of usefulness to cities and thanks to the shemozzle that has been the past twelve months in big ticket transport projects in Victoria, at a high level we now know both types of projects have a similar cost to build, especially when tunneling is involved.

East West Link's eastern section was priced around the $1 billion a kilometre mark and the Melbourne Metro Rail (MMR) project is similarly costed around the $1 billion mark. The benefits of the MMR project are to be felt across 100km of railway line between Pakenham/Cranbourne and Sunbury but at a very high level; one that is no doubt easily understood by the wider public, six lanes of freeway in a tunnel is roughly the same price (on a per kilometre basis) as two rail way tracks in tunnels.

If we assume the cost-benefit ratio of the Melbourne Metro Rail project will be similar to that of the same project Infrastructure Australia assessed a few years ago then we know that the Victorian public is going to derive a positive return out of investing in Melbourne Metro Rail as opposed to the East West Link.

But by the same token, we shouldn't gloss over how incredibly expensive expanding our existing rail system to the same specifications as our existing network is.

Should we continue doing this with newer railways?

There comes a point where someone has to say - and I'm not the first - new branch lines (Ballieu/Napthine Government studies into Rowville and Doncaster) or entirely new rail lines (such as orbital lines) is going to be prohibitively expensive and inevitably result in long delays between projects.

Yes, we could implement a value-capture regimes around new and improved public transport infrastructure to help recover the cost of building new or expanding railways. We could also raise money by applying specific levies broadly across a geographic area, on businesses or residents. All quite legitimate.

However why raise that money to pay for, all intents and purposes, legacy infrastructure? Targeted value-capture regimes and broad-based levies should be the weapon in the arsenal that allows us to build railway infrastructure in greater volume, not simply be used to pay a high price for an expanded network that would allow interoperability between existing and new railway lines.

Breaking with tradition

Sydney has started to break with traditional railways construction with the advent of the North West Rail Link. They're going back to the future and ditching the idea of building a new line that would work with existing rolling stock, signalling systems and rail operations. The line will do away with train drivers altogether and be operated remotely.

The headline price is $8.3 billion dollars yet it includes 22km of new track (15km of which is in tunnels), eight new stations and the conversion of the existing tunnels from Epping to Chatswood to support Alstom's Metropolis class trains and associated signalling and safe working system that will operate the services once construction is complete.

It's a bit unfair to compare directly to the MMR project as the North West Rail Link is located outside Sydney's city centre and the MMR is right in the middle of ours; but the ​freely available data on the different components of the NWRL could prove very useful should any state government re-look at Doncaster and Rowville; both of which I'd argue are very similar projects to the NWRL.

But wait, there's more

Back in May 2013, Alstom launched its Axonis 'light-metro' solution. Axonis is the name given to an integrated solution which includes using trains from its Metropolis product suite, a slim profile viaduct / elevated guideway structure designed by Alstom's construction subsidiary Bouygues, a power supply system, a track laying system and Alstom's new 'Urbalis' communications-based train control system.

The marketing material for Axonis includes the following figures:

• Viaduct/guideway is 6.8 metres wide (a little more than the width of two car lanes). To compare to the North West Rail Link, its elevated "skytrain" section is reportedly to have a width of 11 metres.
  • The difference in width in this scenario can be put down to the design of Axonis: evacuation, if required, will be through the front/read of the trains, not onto a walkway beside the track which will span the length of the viaduct in the NWRL's case.
• Track is designed to be 10-14 metres above ground in an elevated scenario and the pylons which will support the viaduct have a diameter of 1.6 metres. This could fit in many different arterial road medians around Melbourne.
• Most interestingly the design has a minimum curve radius of 45 metres. It would impact speed and therefore journey time if many of these tiny curves were present along any route but it demonstrates high flexibility when it comes to installing the viaduct in built up areas above road medians.
• The trains are designed to be powered by a third rail system thus reducing the overall visual impact of the viaduct (no overhead catenary protruding above the rail deck); one assumes there's a safety protocol which would shut the power off should evacuation of the trains be required!
• The track configuration is an international standard. We call it standard gauge around these parts and it can run through a tunnel or on the surface if required, on impressive 6% grades as well.
• The Metropolis class trains are 2.7m wide (compared to Melbourne trains: Siemens (2.95m), X'Trapolis and Comeng (3.05m)) and run in two, three, four or five car lengths. Each car is 18m long (compared to 24m in existing Melbourne trains)
  • Each car is reportedly able to carry a maximum of 200 passengers with a very squeezy crush capacity of six passengers per square metre.
  • A five car train would have a crush capacity of 900-1000 passengers and be a total length of 90m compared to a similar crush capacity across existing trains on Melbourne's train network which measure approximately 145 metres.
  • The Urbalis train control system utilised in this type of setup is reported to allow headways of 60 seconds to be achieved.
• Overall the system is designed to carry between 10,000 passengers per hour per direction in a two car train configuration and up to 45,000 passengers per hour per direction in a five car train configuration.

One thing that sets this total transit solution apart from many others like it, Alstom offer this on non-proprietary terms, meaning owners of the system are not locked into a specific vendor when they need to extend the track or upgrade, replace or expand the number of train vehicles.

​Although the name is not mentioned, it appears Riyadh's new six line, 176km long metro system is to be the first system at least in part built utilising all the components that Alstom brings together under the Axonis brand. In a 2013 media release, Alstom announced it had won the contract to equip three of the six lines with its system at a cost of €6 billion.

A Railway-Technology article provides a little more information on the Riyadh project, key among the features listed is that the tunnels which will be built on the three lines which Alstom is directly involved in will have a diameter of 10m, a single tunnel bore catering for two tracks. Sydney's North West Rail Link will be built with twin six metre internal diameter tunnels.

Comparing construction costs between Saudi Arabia and Australia is naturally fraught with danger (I recommend reading Alan Davies' thoughts on the comparison of rail construction costs) but it appears everything about the Axonis 'package' is highly targeted at all the cities which don't currently have a traditional heavy rail metro and are looking to cost effective solutions to bringing more rapid transit to the masses. That's us.

All of the above, on paper at least, point to likely lower construction and operational costs compared to our existing rail system given the Axonis (and other systems like it from other vendors) is driverless, light-weight and involves smaller stations compared to the size of stations on Melbourne's existing rail network and the enormous stations that are reportedly to be built for Melbourne Metro Rail.

Employing turn-key rail systems like this to mooted (PTV or otherwise) new rail lines could possibly shift the economics and therefore cost-benefit ratios to an even more positive level.

Is it time to re-think the way we want to expand our rail network?

Lead image credit: Alstom.