The Courier offered a slightly tongue-in-cheek summary of the debate earlier this year to help sort through the often technical issues.

Help! I'm hearing all this stuff about fast trains, airport links, tunnels and commuting from Ballarat. But I don't really get it. Can anyone explain?

Don't worry, you're not alone. It's one of the more complicated infrastructure issues involving Ballarat. We're happy to give it a go.

Thank you. I think I have understood that this is not just about fast rail to Ballarat?

Spot on. The service to Ballarat is just a part of infrastructure planning with a whole bunch of moving parts. These include access and frequency of services to the rapidly expanding outer suburbs, as well as regional cities such as Geelong and Ballarat. At the heart of much of the recent debate are plans for the much talked about Melbourne Airport Rail Link, a project that has been discussed since 1963. Rather embarrassingly for the state, still does not exist.

I see. Actually, no I don't. What has getting to and from Ballarat got to do with the airport?

It's mostly about Sunshine, referred to as a "superhub" station, which would be used as an interchange for trains travelling between Southern Cross and the airport. Sunshine is also on the Ballarat Line, so the way trains get to and from that station affects the way we Ballaratians get into central Melbourne.

Aha, Sunshine. But I still don't see the light. What's going on at Sunshine?

Well, that's the crux of the matter. Until recently, it seemed likely that two new sets of tracks would be built there from Southern Cross Station, mostly in a new tunnel under the inner west, and partly on an overland stretch. These would allow airport trains to get there, potentially directly, and more quickly than they could using the existing rail lines. A private consortium, which includes Melbourne Airport, is pushing to build those tracks and run the trains.

Good for Sunshine and airport passengers. But how would it help Ballarat commuters like me?

This is the key. In theory those new tracks could also be used by regional train services including commuter trains to Geelong and Ballarat, between the airport trains. Not only would they increase capacity, the tracks would also probably be direct - most likely bypassing Footscray - allowing for a quicker exit in and out of Southern Cross Station. Another aspect is the scope for extra capacity at Southern Cross Station, where regional trains end up. Extra platforms, if built, would allow more arrivals and departures from a busy station that is already close to capacity.

OK, got it. This all sounds pretty good to me. What's the catch?

The catch is, it may not happen. The state government originally said that was the preferred route, but now seem to be going cold on the idea - although they keep on insisting that all options are still on the table.

Meanwhile the federal government, which is stumping up $5 billion of the funding, is no longer insisting on the tunnel option quite so loudly (it did so as recently as September last year, when Prime Minister Scott Morrison outlined his support for a "quick link to Tulla".)

Oh, let me guess: this is about money, right?

Pretty much. You may have noticed that tunnels are not going too well for the state government right now, with a ballooning budget for the West Gate Tunnel (by road) and the Metro Tunnel (for trains). So it's perhaps unsurprising that the appetite is not there for another risky super-infrastructure project. The prevailing idea seems to be at the moment that the airport rail link will go through the Metro Tunnel.

Right. Why's that a problem?

So, if the airport trains join the Metro Tunnel at Sunshine, it means there won't be extra tracks from Sunshine to Southern Cross - instead, the airport trains will be running with the big new metro trains, and us regional commuters will have to stick with what we've got for the moment.

Well, that's not so bad is it? I just checked a timetable and trains (in theory), currently take only 13 to 17 minutes between Sunshine and Southern Cross. So we're only talking a few minutes difference, right?

Not necessarily. Experts reckon those tracks, which were put in place to bypass Metro stations a few years ago as part of the Regional Rail Link, are already hitting capacity.

So it leaves very little wriggle room if transport planners want to schedule more trains.

Others point out that capacity on the existing line could improve in the future.

However, advocates for extra tracks in a new tunnel from Southern Cross Station - such as Committee for Ballarat CEO Michael Poulton and the Rail Futures Institute - argue it would "future-proof" rail services from Sunshine to the CBD, allowing more room for frequency to be increased and reliability maintained in the decades ahead.

I see. But it's not looking likely, is it?

If the rumours and leaks are to be believed, no. But there is intense lobbying underway, especially as state and federal budgets and the business plan for the airport link are being considered. This is a project that Mr Poulton has banged the drum most loudly. The City of Ballarat has also just articulated its stance on the airport rail link for the first time, although it stopped short of advocating for a new tunnel from Southern Cross Station.

OK, so that's Sunshine explained. What about the rest of the journey between Melbourne and Ballarat. Sunshine is only a small bit, right?

Very good point. In fact, arguably the biggest thing in the pipeline for Ballarat commuters is the proposed electrification and quadrification of the tracks between Melton and Sunshine, which would allow express regional trains to run through.

Quadrific-awhatty? You've lost me.

Sorry. Electrification would mean electric Metro trains could use the tracks up to Melton. Quadrification - also called quadruplication - basically means laying two new sets of track - ie four rails - effectively giving a whole new line for fast regional trains. These would then be able to bypass slower suburban trains. Combined, these should relieve a lot the pressure on existing regional services. Note that brand new stations, like Cobblebank, already have space for extra tracks to go around them.

Good stuff. But aren't our V/Line trains electric?

Nope, they're diesel. But they could be electric, or hybrid with both, in the future. Here is what it says in the Western Rail Plan: In planning for fast rail to these regional centres, all options would be considered. This includes electrification to Geelong and Ballarat with fast, electric regional trains.

Right. So we don't know how far that is down the, er, track?

The electrification of regional rail lines is at the ideas stage at the moment, but the separation of the tracks is already being planned. In the last budget, the State government announced $100 million to go towards the planning and design of the Western Rail Plan, which is looking to separate regional and metro services going towards both Geelong and Ballarat. For Geelong, the current scope is from Sunshine to Wyndham Vale, for the Ballarat Line it is from Sunshine to Melton. Keep in mind Wyndham Vale and Melton are among the fastest growing areas in Australia. The planning is happening in conjunction with budget planning for the Airport Rail Link.

READ TRANSPORT FOR VICTORIA'S WESTERN RAIL PLAN

Full circle back to the airport rail link. I feel slightly dizzy.

Deep breaths. Let's move away from the airport link, and concentrate on the separation of the tracks, which in theory should be a very good thing for Ballarat commuters. The Ballarat convenor of the Public Transport Users Association, Ben Lever describes electrification and quadrification between Sunshine and Melton as the most important thing for travel to and from Ballarat: He said: "This would move Melton and other suburban passengers onto the Sunbury line, and free up a huge amount of capacity for Ballarat trains to get a quick, clean run into the city - regardless of what happens with the airport."

OK. And just how much of a priority is Ballarat fast rail?

It's up there, but the state government has explicitly said Geelong comes first. In black and white, stated in the Western Rail Plan, fast rail to Geelong is cited as "the highest strategic need due to the city's growing population." Prime Minister Scott Morrison has also put $2 billion on the table for fast rail to Geelong, which we reckon the state government's pretty keen to put to good use as soon as they can.

Wait, didn't they just build a whole lot of new stuff on the Ballarat line? I had to take rail-replacement buses in December!

That was the $500 million Ballarat Line Upgrade, which is pretty important too. Wendouree station was rebuilt, and there are better stations and parking at Ballan and Bacchus Marsh. They also built more passing loops so trains don't have to wait for each other to go past, which is good for improving frequency, and there were more upgrades closer to Melbourne.

So when will we know more?

The business case for the airport link will be out in March and a call one way or the other seems imminent.

Thank you. And then will it be, er, full steam ahead?

Probably not quite the right phrase. But we know what you mean. One would hope work will be under way by the 60th anniversary of the idea of an airport rail link (in 2023). But like any timetable, we suspect this may be subject to delays.

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