Melbourne needs better cross-city public transport, but the Andrews government’s promise to build a single suburban orbital rail “loop” isn’t the way to provide a real solution. Despite the eye watering cost, it doesn’t even come close.

The promise is proving popular politically but the real benefits look very modest in absolute terms and positively miniscule relative to the massive cost. The claim that there’ll be 146 million trips on the line in the year it’s fully completed is implausible; it would do Trump proud.

That’s more than three times as many departures/arrivals as currently pass through Sydney’s domestic and international airports combined, and 15 times as many trips as airport users make on Sydney’s airport train. It’s more than the number of trips on 14 of the Paris Metro’s 15 lines (a city where driving is far less competitive relative to public transport than it is in suburban Melbourne).

That’s not to say the governments loop is without any merit; its key advantage is providing a suburban link between most of Melbourne’s existing radial train lines. But the benefits from a building a single rail link at a substantial distance from the city centre aren’t even remotely commensurate with the generational-scale of funding required.

This promise only provides one rail line. Better than nothing you might say, but it still leaves substantial dead zones without high quality public transport. For example, there are no works in this promise to provide better cross-town transit in the 14 – 19 km gap between the CBD and the first stage (Cheltenham to Box Hill). It still leaves a similar gap in the outer suburbs that stretch out even further beyond the proposed alignment.

Nor does it do much for those who don’t live close to a rail line. Most rail users live within a kilometre of a station, but even most of those lucky enough to live on the planned route won’t be able to walk to a station – there’s a 6 km gap between Cheltenham and Clayton stations, 9 km between Box Hill and Heidelberg stations, 10 km between Reservoir and Fawkner stations; and 13 km between the (new) Airport and Sunshine stations.

Of course no government can feasibly construct a dense grid of cross-city services if they all have to be heavy rail, much less underground rail. Even with a paltry 15 stations in 90 kilometres, this one will cost at least $50 billion.

That’s a massive expenditure. It’s three times the size of Rudd’s GFC-avoiding BER program. It’s close to seven times what it would cost to double the number of trams in Melbourne. It’s enough to build 500 public hospitals or 2,500 suburban public high schools. As I noted last time, it’s the same as the estimated cost of building a 750 km High Speed Rail line between Sydney and Melbourne (see Has Daniel Andrews gone loopy on rail?).

Melbourne simply can’t hope to replicate something like central Paris, with its network of 15 criss-crossing underground rail lines and 303 stations. The Paris Metro only covers the central 5 – 6 km radius, about 100 sq. km. Melbourne’s built-up area is orders of magnitude larger; about 2,500 sq. km. Melbourne is also notable for its sprawling footprint whereas Paris is one of the densest cities in the developed world (see Can we build a Metro just like the one Paris’s got?).

Progressives shouldn’t be blinded by the glamour of the Andrews proposal. There’s a much better way that would cost considerably less and provide much greater benefits.

Progressives should demand a ‘grid’ of high-quality light rail and bus services providing frequent “turn up and go services” so public transport travellers can go from “anywhere to anywhere” in the metropolitan area. They should call on the Andrews government to  blanket the metropolitan area with high-quality services every 2 kilometres or so in both directions and provide a stop every 1 – 1.5 km in every direction on all routes.

A ‘grid’ like this would put every household in Melbourne, no matter how far they live from a rail line, within walking distance of a frequent service at both the origin and the destination of their journey. It would provide a cross-town connection every two kilometres with all the existing radial train, tram and BRT lines right through from the inner city to the outer suburbs. Crucially, it would also provide additional high-quality radial services in the extensive gaps between rail lines.

It wouldn’t be as speedy as a train, especially one that only stops on average every 6 km, but light rail and buses can be made faster and more reliable by giving them exclusive road space, priority at intersections, and grade separation at key road junctions. Rather than the often meandering and frequent stops that characterise some current tram and bus services, routes would be direct with stops spaced at useful intervals e.g. 1 to 1.5 km.

There’s no doubt it would be costly to set up such a ‘grid’ e.g. rolling stock, tracks, roadworks. But even if an outlay of as much as $25 billion for a mostly light rail network is assumed, the pay-off would be huge: it would provide public transport users with a much greater level of accessibility than the lone suburban rail line the Andrews government is promising to build.

Giving public transport greater priority on roads as I’m proposing would necessarily impact motorists. Fear of offending drivers is why governments routinely and ineffectually throw money at the problem rather than do what would actually work to reign-in excessive consumption of road space.

It would be difficult politically, but politicians shouldn’t be given a free pass to splash around huge licks of public funds to shore up their political fortunes. Relative to the Andrews loop, the ‘grid’ would use roads more efficiently, provide a complete public transport network giving users access to the entire city, and at last offer a more competitive alternative to cars for cross-town trips (see also Is congestion charging a good idea? and Is congestion charging too inequitable?).

We need to think of public transport as a network that provides synergies. We won’t get the “network effect” in a metropolis like Melbourne unless we’re prepared to embrace multiple modes and, importantly, constraints on car use (see How can public transport work better in cities?).