Geotechnical investigations complete, Metro Tunnel construction to ramp up

Geotechnical investigations complete, Metro Tunnel construction to ramp up
Alastair TaylorMarch 22, 2017

You've probably heard of it by now - that new rail tunnel that's set to run through the city.    

The State Government has today announced geotechnical investigations are complete which will lead to the acceleration of the early works that have been slowly turning over for a while now in the CBD.

Things are about to become just that more real, more visible.

If you frequently travel to the city, the two sites which have seen some level of preparatory works already at both the top and bottom end of Swanston Street - Melbourne Central and Flinders Street Stations - will become construction focal points from this point on.

A spokesperson for the Minister for Public Transport and Major Projects confirmed the largest component of the entire project, the PPP contract for the civil works to construct the tunnels and stations, is still accepting bids until next month.  

A decision to announce the successful bidder is expected by the end of 2017 with the tunnel-boring machines expected to be let loose under the city sometime in 2018.

Geotechnical investigations complete, Metro Tunnel construction to ramp up
Expected capacity improvements after the Metro Tunnel is operational

The network map above, posted on the front page of the Metro Tunnel project's website, illustrates the capacity improvements expected once the metro tunnel is operational.

Based on previous announcements, we know that the Pakenham/Cranbourne-Sunbury line that is created as part of the Metro Tunnel project will have a modern signaling system which does away with blocks and allows trains to run closer together.  Government information released to date put this new capacity on rail lines using the new 'High Capacity Signalling' system at 24-30 trains per hour (a train every 2-2.5 minutes).

The current signaling system can 'safely' handle approximately 20 trains per hour according to published government information on the topic.

The Frankston, Sandringham, Craigieburn, Werribee/Williamstown and Upfield lines are set to see some infrastructure improvements which will allow more trains to run shorter runs on their respective lines: Cheltenham on the Frankston line, Essendon on the Craigieburn line, Gowrie on the Upfield line were all mentioned in the Metro Tunnel business case.

Of all the lines and the respective capacity improvements depicted on the map above, Upfield is a stand out.  This is most likely because it's coming off a very low base: there are only 3 trains per hour between 7am and 8am and 4 trains per hour between 8am and 9am at present.  

With 3400 units in 47 projects located in Brunswick & Coburg in the development pipeline, the extra services - likely to be a train every 10-12.5 minutes based on the capacity improvement number - are well and truly going to be needed.

Alastair Taylor

Alastair Taylor is a co-founder of Urban.com.au. Now a freelance writer, Alastair focuses on the intersection of public transport, public policy and related impacts on medium and high-density development.

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