Big transport infrastructure projects tend to follow the same narrative as an episode of Grand Designs. Just as each home builder ends up admitting to Kevin McCloud that they have vastly outspent their original budget and wildly overrun their build time, so ambitious public transport schemes seem to come in way later and at a far higher cost than originally projected.

But while Berlin’s airport is more than four years late and Edinburgh’s truncated tramline cost £375m more than forecast, on Monday a whole new Metrolink line will open in Manchester over a year ahead of schedule.

With 15 new stops along nine miles of track, the £400m Manchester airport tram link runs from Cornbrook, a rather desolate interchange just down the canal from the city centre, all the way out to the airport. It passes through the bohemian district of Chorlton, skirts around Tory-voting Sale, ploughs on through Baguely and the sprawling housing estates of Wythenshawe, via the excellently named Shadowmoss stop, before reaching the UK’s biggest airport outside the south-east.

So how has Manchester succeeded when so many other cities have failed? Easy, said Jon Lamonte, chief executive of Transport for Greater Manchester, which runs the transport network on behalf of the 10 local authorities. The government trusted his team to get on with it rather than trying to micromanage everything from Whitehall. “What it reflects is how successful we can be when Greater Manchester is given the funding and power to build something ourselves,” he said. “It shows the power of what you can do on a local basis.”

While £400m is hardly peanuts, it’s a bargain really, insisted Andrew Fender, chair of the Transport for Greater Manchester committee, as he gazed lovingly out of the window of a yellow tram on a test run to the airport last month. “There are signalling projects on the London underground that cost more than it’s taken us to build the whole airport line,” said the Labour councillor, who has spent 37 years on Manchester city council pushing for better public transport.

But Lamonte is not resentful of the huge amounts spent on transport in London compared with the north of England, such as the £1bn for just two tube stations on the Northern Line extension to Nine Elms. “We don’t say move money from London to here. Both Manchester and London have to grow so that the national economy grows,” he said, insisting that he and Peter Hendy, who runs Transport for London, speak “as one”. He added: “Peter is as keen on the developments up here as in London because he recognises that if the whole economy does well then London can grow, we can grow, the national economy grows and we all benefit.”

The new line brings the size of the Metrolink network to 57.5 miles, serving 92 stops, bigger than any comparable system in the UK, including the Docklands light railway in London. After opening in 1992 it has recently expanded at a remarkable rate. Since Lamonte took over two years ago, new lines have been opened going out to Ashton-under-Lyne in the east, Oldham and Rochdale in the north, and East Didsbury in the south. Passenger numbers are up from 22 million to 30 million in just two years.

The rapid expansion has been partly funded by an innovative deal the Greater Manchester combined authority struck with central government. Under Earn Back, a “revolving infrastructure fund”, the government funds infrastructure projects which the local authority promises will generate economic growth. The Treasury is happy because this growth generates tax revenues through greater employment, business rates and greater prosperity – a proportion of which the exchequer gives back to Greater Manchester, allowing it to reinvest and develop further schemes.

Greater Manchester plans to use the Earn Back model to fund another line out to the Trafford Centre shopping mall via Trafford Park industrial estate and the Imperial War Museum, and is constructing a second city-centre crossing to ease peaktime congestion.

It is thinking like this that has made Greater Manchester George Osborne’s pet city region, and one of the main reasons why it is expected to be given significant devolved powers by the chancellor later this week. Osborne has already said that building what he has dubbed a “northern powerhouse” will be at the centre of his autumn statement in December. As Lamonte puts it: “Strong civic leadership breeds confidence from government to allow us to get the funds, to allow us to do what we want. That’s why we look forward to the autumn statement with a good deal of anticipation because we know that there are going to be some good things in it for us.”

But despite all this big talk, some in Manchester are unimpressed by the new Metrolink line, balking at the fact it trundles along so slowly that it takes 45 minutes to get to the airport from Cornbook, while an airport express train takes just 15 minutes. It will be more expensive, too: £6.20 return on the tram compared with £4.10 on the train. The naysayers are missing the point of the line, says Fender. “This isn’t so much about getting people to the airport from the city centre but about connecting communities on the way to the airport. For Wythenshawe in particular, Metrolink will provide new and easier ways for people across Greater Manchester to reach the town centre and all it has to offer – as well as making it a more attractive place to live, work and do business.”

It is a scheme for the future as much as the present. Under construction is a commercial district dubbed Airport City, which it is hoped will generate thousands of jobs for people in the surrounding areas, way beyond those directly connected with the airline industry. This sort of foresight has served Greater Manchester very well in the past – it built a line to Salford Docks when it was a post-industrial ghost town. Now it’s called Media City and is home to the BBC.

Metrolink

• Opened in 1992 (additional Second City Crossing – 2CC – under construction for 2017)

• Currently seven lines covering 57.5 miles (60 miles with 2CC) / 92 stops (93 with 2CC) / 120 trams

• Circa 30 million passengers 2014

Docklands Light Railway

• Opened in 1987

• Currently seven lines covering 21 miles / 45 stations / 145 vehicles

• Circa 100 million passengers (2013)

The Sheffield Supertram system

• Opened in stages between 1994 and 1995

• Currently three lines covering 18 miles / 48 stops / 25 trams

• Circa 14.4m journeys 2012/13

The Midland Metro system

• Opened 1999

• Currently one line covering 12.5 miles / 23 stops / 20 trams

• Circa 4.8m journeys 2012/13

The Nottingham Express transit system

• Opened 2004 (additional routes are under construction for end of 2014)

• Currently one line covering 8.7 miles (19.5 miles with expansion) / 23 stops (51 with expansion) / 15 trams (37 trams with expansion)

• Circa 7.4m journeys 2012/13

Edinburgh trams

• Opened 2014

• Currently one line covering 8.7 miles / 15 stops / 27 trams

• Circa 1.5 million passengers in first 100 days of operation

(Figures supplied by Transport for Greater Manchester)

• This article was amended on 2 November 2014 because an earlier version said Ashton-under-Lyne was to the west of the city centre. This article was further amended on 6 November 2014. The £6.20 fare from Manchester Airport to the city centre was for a return ticket on the tram, not for a single as an earlier version said.