Half of the Melbourne Airport Rail Link is currently under construction

....in the form of the Regional Rail Link.

What is the RRL and how is it relevant?

The Regional Rail Link (RRL) project is a Kevin '07 stimulus project that aims to separate V/Line-regional traffic heading to Geelong, Ballarat and Bendigo from metro traffic by building one new track pair all the way from Southern Cross station to Tarneit via Footscray, Sunshine and Deer Park.

When built, all V/Line traffic heading to Geelong, Ballarat or Bendigo will use this track enabling faster regional journeys and just as important: freeing up capacity on the Werribee and Sydenham metro lines so frequencies can be increased on these lines.

In short RRL is a big shot in the arm for rail capacity in the western suburbs.

Current V/Line operations - without the RRL

The following is a snapshot of what the current timetables on the Geelong, Ballarat and Bendigo lines between 5 and 6pm on a weekday look like - it's to be expected that the same or very similar levels of service will be using the RRL once it's opened for business.

• Geelong - 5 trains per hour (TPH): 4:57pm, 5:08pm, 5:21pm, 5:32pm, 5:54pm
• Ballarat - 4 TPH 5:07pm, 5:22pm, 5:52pm, 6:02pm
• Bendigo - 3 TPH 4:57pm 5:28pm 5:48pm

So by the time the RRL opens, out of a potential 24-30 train paths (a train every 2.5 minutes or 2 minutes hurtling down the RRL tracks), only 12 will be used (5 + 4 + 3)

In summary the track will only have up to 50% of its capacity used if you assume the same or similar timetable will be used upon opening.

Fast forward three decades post RRL completion and for argument's sake lets say Geelong, Ballarat and Bendigo double in population and the service level also doubles notwithstanding the option of also extending train lengths for more capacity:

• Geelong 10 TPH
• Ballarat 5-6 TPH*
• Bendigo 5-6 TPH**

_{*By then, Melton trains won't be using the RRL tracks in the city as they'll have been electrified, and potentially even Bacchus Marsh.}

_{**An extra Kyneton terminating train.}

Assumption total: 20-22 trains per hour will be using the Regional Rail Link tracks between Southern Cross and Sunshine in three decades.

The missing link

The Bracks/Brumby governments identified the Albion corridor as their preferred corridor to link Tullamarine with the city and this has recently been confirmed by Baillieu/Napthine government.

The recent study has shown that the favoured option is to have new track built alongside the existing freight lines, where the new track would leave the Sydenham/Bendigo corridor near Albion Station and then travel alongside the existing dual gauge freight lines.

A new bridge over the Maribyrnong River would be required, and the extra track would run under Keilor Park Drive and the Calder Freeway, at which point the line would ramp up onto an elevated section to traverse the Western Ring Road and Airport Drive and utilise the wide corridor that exists there and then come back down to earth on the southern boundary of Melbourne Airport's land at Sharps Road.

It's anticipated the line would travel through the airport land and would tunnel underground 1km before the Tullamarine Airport terminal station.

The Airport's own master plan appears to take into account an underground station, however it is curious why this is so when an elevated structure would require less capital expenditure and the airport is similarly planning to build a giant elevated road network to service the new parking facilities opposite the new Terminal 4.

Who should operate the "Tullamarine link"?

V/Line. Upgrading the signalling on the new Sunshine-Southern Cross RRL track would allow more frequent trains and why bother throwing up catenary above the RRL between the City and Sunshine (or add another branch line to the Sydenham Metro tracks) when V/Line is perfectly capable of operating the service at higher speeds than Metro?

No point adding yet another class of rail vehicle to the network to intermix with existing Metro Trains - and the Melbourne Airport Rail Link (MARL) study said itself the opportunity for express services will be limited if the Airport Line mixed with Sydenham (or Craigieburn) services.

V/Line's fleet of Dandenong-built Vlocity class trains would fit the bill perfectly because V/Line trains are built for extra luggage (which airport services require).

What about V/Line-Regional operating patterns?

Well as I stated earlier, when the RRL goes live, only half the capacity will be used from day 1.

If you assume a 15 minute service from Southern Cross to the airport, that would bring the earlier total of 12 Geelong/Bendigo/Ballarat services up to 16.

If you fast forward 30 years to the regional service projections I came up with earlier, of the 20-22 Geelong/Bendigo/Ballarat trains per hour using the City-Sunshine section of the RRL plus 4-6 TPH going to the airport we're looking at finally reaching the absolute capacity.

It appears that the RRL tracks out the back of Werribee will be used for stopping trains to service the new suburban subdivisions - let's hope this is only temporary and the corridor is quadruplicated sooner than later so the Werribee Metro line itself can operate the services and the RRL track gets back to actually separating Metropolitan and Regional services.

This peak capacity scenario would be made easier by eliminating all V/Line stops at Footscray and instead expanding Sunshine station and making it the only non-city stop in the metro area for regional services, because....

You hit two birds with one stone

Having all regional services (Geelong, Bendigo and Ballarat) stop at Sunshine, as well as having all City - Airport services stop at Sunshine allows connectivity for the inner-city, North Eastern and South Eastern quadrants of the metro area (connecting at Southern Cross or Sunshine via Melbourne Metro tunnel) a quick non-road based transport solution to Tullamarine as well as offering a one change service for people travelling from the regional cities to Tullamarine.

Wait times at Sunshine would be minimal if a 15 minute, or even better a 10 minute frequency of service ran for City-Airport - Assuming a 5-6 TPH frequency for Geelong, the average wait time would be 5 minutes, Ballarat and Bendigo in the order of 7 minutes would be the average wait time.

A potential timetable departing Southern Cross could look like this:

City to Airport Rail services must be fast and express to make the case for attracting patronage.

The MARL study claimed there would be limited opportunities for express City-Airport services if Metro (and the Metro fleet) were to operate the services and the same South-East connectivity can be achieved by passengers on the Pakenham/Cranbourne lines changing trains at Sunshine using the V/Line & RRL track option.

The Baillieu/Napthine Government's MARL study also identified the possibility of creating a new MYKI zone for this purpose and we, the travelling public, should make it absolutely clear that this should be a modest increase, not just another revenue stream for the entity that owns the lease over Tullamarine airport.