Some time in the next few years, she said, trackwork could take place "in the middle of the night when there are no trains running" rather than on the weekend, forcing thousands of us onto crowded and slow replacement buses. Illustration: John Shakespeare Well that hasn't happened. And it's not the only commitment the state government might hope has been forgotten. In the same year, for instance, Berejiklian said there would be 24 trains an hour running in each direction along the north shore by 2019 – that's up from the current 18 an hour.

That would mean one extra train every 10 minutes. On the current state of works, there's no chance those extra trains will be running by 2019. Which platform will you head to? Credit:Daniel Munoz By the standards of most administrations, Mike Baird and Barry O'Farrell's governments have been reasonably coy about making outlandish promises. But Baird is sitting on a big one. And the refusal of his government to attempt to justify it demonstrates what has to be considered a remarkably cavalier approach to public money. Take the below:

The major issue at last year's state election was Baird's promised privatisation of electricity assets.

The major project to be built with the funds from Baird's privatisation of electricity would be a new $10 billion or so rail line through the city.

The major claim made for this new rail line, repeated ad nauseam by Baird, was that with a few unspecified works on the Western Line it would boost the capacity of Sydney's rail network by 60 per cent. It was probably a failure of the media (and this journalist) that that 60 per cent claim was not scrutinised much at the time. But the need for another rail line through the city has been well established for decades. And the government was certainly making impressive construction progress on other rail projects – the North West Rail Link in particular. So the 60 per cent figure was allowed to stand, despite private doubts among some in the transport industry about its bona fides. Nevertheless, a few months ago I put in a freedom of information request asking for analysis from 2014 or 2015 and not-for-cabinet discussion (departments don't release anything with the word "cabinet" on it) that supported the 60 per cent claim.

The response was that there was none. "I am informed by the Freight, Strategy & Planning Division that there is no information which falls within the terms of the application which was prepared in 2014 or 2015," a Transport for NSW officer wrote. But the officer's response indicated there might be earlier work along those lines. So I submitted another application asking for any analysis prepared in 2011, 2012 or 2013 supporting the 60 per cent claim. The department then provided one document that, like Baird at the election, asserted there would be a 60 per cent increase in capacity but did not demonstrate how this was achievable. Since receiving these responses I've oscillated between a couple of attitudes. On the one hand: who cares? Baird's building a new train line. The line will obviously create a huge increase in capacity. That has to be a good thing.

But on the other hand, why shouldn't they justify $10 billion in public spending? This is particularly so when, as they're doing here, the line involves a controversial cannibalisation of existing services. The line will be run by new private metro operators that will take over two existing lines: the Epping to Chatswood and the Bankstown. I don't have a problem with companies running transport services. But the problem is when transport services are structured in a way to make it easier for companies to build and run them, at the expense of what is best for people who need to use them. Which is the fear with the current proposal. South of Sydney Harbour, the new metro line is to join with the Bankstown Line – the least busy of Sydney's main railway lines. So how will the new line improve the travelling experience for the tens of thousands of Sydney residents using the busier Western Line and Campbelltown and East Hills Line?

That's what is at the heart of the 60 per cent issue. How will this new line improve services for anyone who doesn't live on it? Baird has said the line will increase services by 60 per cent on "every rail line in Sydney". That is plainly false. But what is the right answer? What will the impact be? Despite $10 billion, the government either can't or won't say. In a response for this column, Transport for NSW provided some numbers. The department said there were 120 rail services entering Sydney in the busiest hour in the morning, and the new line would create the capacity for another 60 more – 30 per hour in each direction. But that's only true, really, if you don't think about it. The Bankstown Line already runs about 16 peak hour trains in both directions – so the 60 "new" services would really be only 44 – and that's less than a 40 per cent increase.

Which is another thing to get angry about if you're on a trackwork bus this weekend. Jacob Saulwick is the city editor.