Nearly a quarter of a century ago, two suburban railway lines, to the north and south of Manchester, were joined via new tracks through the streets of the city centre, and converted for light rail operation. In 1992, for the first time in decades, trams returned to the streets of Britain.

The Metrolink network was extended in 1998; and in 2010; and again, in every year since. The latest line, to Manchester Airport, opened earlier this month. More are in the pipeline.

In other words, Manchester has managed to do something that no other British city has done since London built its tube. Some cities have opened individual light rail lines; other have rebranded railway lines as metros as a one-off event. But Manchester alone has succeeded in creating something that's a real network, with all the multi-coloured Beck-style maps that implies, and then continuing to build it year after year after year.

All of which raises a question: what did Manchester get right?

To prevent the place from getting too big-headed about the fact we're being so nice about it, we’ll be explaining this using quotes from the most famous people ever to come out of the city’s arch rival.

1) You say you got a real solution – we'd all love to see the plan

Let’s start with the history. Once upon a time, Manchester effectively had two railway networks. One covered the north of the city, and ran into Victoria station; the other, covering the south, ran into Piccadilly. As a result, passengers arrived outside the main business district and had to walk the last leg: not ideal, if you want to encourage people out of their cars.

The city explored a number of options for plugging this hole, most famously the Picc-Vic tunnel, a sort of Mancunian Crossrail. But by the early eighties, the city’s transport authorities had settled on light rail, of the sort that was becoming increasingly popular on the continent. In 1984, it published its plan for a 100km network, mixing existing railway lines with new, on-street sections, and running to a total of six destinations in the city’s suburbs.

Three decades later, four of those routes (Altrincham, Bury, East Didsbury and Oldham) are a reality. In other words, the city made a plan, and adapted it to circumstance. At no point did it throw it out and start all over again.

2) Now give me money

Getting any cash for public transport at the height of Thatcherism was always going to be a tough sell, of course: at the time, in fact, the government was seriously considering closing a number of railway lines in Manchester to save money.

So, says Councillor Andrew Fender, who chairs Manchester’s transport committee and was involved in the scheme from the beginning, the city decided to focus its efforts on “the most economically viable” bit of its network. The commuter railway line to Bury, a suburban town eight miles north of the city centre, used a unique power system and distinctly rusty trains: it all needed to be replaced anyway.

Meanwhile, Market Street, in the city centre, was in the process of being pedestrianised: since the road was being torn up anyway, and since it provided a convenient link to the start of the Altrincham line in the south, it was possible to join the two lines together at a minimum of extra cost. A spur to Piccadilly was included, to link the network to the city's main station.

The future of Metrolink, as envisioned when the first lined opened in 1992. Click for a larger version. Image used courtesy of Transport for Greater Manchester.

From the very start, then, the authorities weren't simply presenting a wish list, or a vision of the city they wished to be: they focused on making the best economic case they could. And so, says Fender, "We were able to persuade the government that this was something they could invest public money in.”

3) And now my life has changed in oh so many ways

This focus on winning the economic argument has continued. Some of the lines on the network today weren't in that original 1984 plan: most obviously, at that time, Salford Quays was a post-industrial wasteland. Within a year or two, though, it was slated to be one of the country's biggest regeneration schemes.

So, says Fender, the other lines in the first draft of the plan were held back, and for Phase Two the city instead prioritised a line through the Quays, and on towards Eccles. Frequent trams to the city centre would spur the area's regeneration; and the consequent economic benefits would justify the cost of the new line.

In other words, it's not enough to have a plan: you need to be flexible enough to adjust it to changing circumstances.

4) Think for yourself

By the late nineties, Metrolink was a success story, Britain had a new government which was rather more enthusiastic about big public transport schemes, and deputy prime minister John Prescott, the man responsible for transport, was encouraging Manchester to think big. Phase 3 was meant to include four different lines, more than doubling the size of the network in one fell swoop. It would cost £489m, yes: but, so the thinking went, the "Big Bang" expansion would bring economies of scale.

It didn't quite work out like that. Construction inflation, increased land prices, and all sorts of other factors meant that costs began to rise. The programme was cancelled; then it was uncancelled, but the government's contribution was capped at a maximum of £520m. In the end, the Big Bang became two, slightly smaller bangs. The government would fund the next two-and-a-bit lines ("Phase 3a"). But to go beyond that, Manchester would need to find its own source of cash.

The city’s first bright idea was the Greater Manchester Transport Innovation Fund: a £3bn plan that matched central government funding with private borrowing, which would be paid off largely through new congestion charge. This, though, was quite a big deal, so at the end of 2008 the city was required hold a referendum on the vexed question of whether Mancunians fancied getting their wallets out every time they wanted to drive into the city.

This went about as well as you would expect.

But, says Fender, "we'd spent government money developing the economic appraisals for each Metrolink extension, each major bus or rail innovation. We weren't just going to stick all that work in a drawer to gather dust".

So the 10 borough councils and the city’s transport authorities teamed up to put together a new scheme. The Greater Manchester Transport Fund pools cash from existing transport budgets, council funds, and, well, basically anywhere else it can get it. But those sources of money include fares: so the better the city’s transport network gets, the more money there is going back into the pot. Manchester is increasingly able to act without handouts from central government.

5) Come together

Metrolink is pretty big these days. But it doesn't even touch two of Greater Manchester's 10 boroughs, and it barely touches the borders of a third.

Nonetheless, all 10 supported the new financing mechanism that has paid for the scheme's expansion. It’s an example of that rarest of things, a virtuous circle: so successful were the trams in helping to regenerate the city centre, that even boroughs untouched by them could see it was worth their while to expand the system.

Greater Manchester has come together in other ways, too. In other cities, a change in which party holds the town hall has seen years of work thrown out. But, says Fender, "Since the late 1990s, we've had support from councils in different parts of the city region, right across the political spectrum. Getting phase one built was absolutely crucial to demonstrate that it would work.”

The single transport fund created in 2009 has had a fairly major side effect: it helped convinced Whitehall that Greater Manchester was capable of a measure of self-rule. If working together made it possible to expand Metrolink, then expanding Metrolink has made it easier for the boroughs to work together, too.

Metrolink today. Click for a larger version.

6) The long and winding road

Peter Cushing, who since early 2013 has been the director in charge of Metrolink, has all sorts of exciting plans for the future. New signalling, to improve reliability; a new western line to Trafford Park, and onto Port Salford, which is currently out to consultation; using “tram trains”, to add lines shared with heavy rail services to the network.

The most immediate priority, though, is finishing the second city crossing, which will enable more trams to run through the city centre, and so allow more frequent services on the network’s outer branches. "We're not in a situation where we stand still," Cushing adds. "We're always looking for opportunities that are affordable, fundable and make good economic sense."

None of the lessons of Metrorail are complicated or surprising: work together; make a plan; stick to it where possible, and adapt it where not; prioritise the bits that’ll do most for the local economy; and never, ever give up. In many ways, the surprise isn’t that it’s worked, but that so few cities have managed to do it.

Fender, who's been there since the beginning, is clearly massively proud of the network he's helped to create. "I would consider Manchester to be the UK's first provincial city," he says. "It has an international reputation now, and a very significant part of what we've achieved has been the light railway." Manchester didn’t just create its trams: those trams have helped create modern Manchester.