And bosses insist the expanding service is set to go from strength to strength.
The tram line, which operates on a mixture of purpose built tracks and reopened conventional rails, had been first mooted back in the early 1980s and was seen as a way of solving the region’s chronic problems with congestion.
Despite a relatively slow take up after the first line between Wolverhampton and Birmingham Snow Hill was opened by Princess Anne on May 30, 1999, few would argue that it has not caught on with the passage of time.
Last year more than seven million people used the 12.5 mile route, which now runs through to Grand Central – the highest figure since its inception and a million more than in 2017.
And that figure is set to grow year-on-year as the Midland Metro Alliance opens up a series of new extensions.
Work is already underway on extensions through Wolverhampton and Birmingham city centres, while a line out from Birmingham’s Grand Central to Hagley Road, Edgbaston, is set for completion in 2021.
Later this year construction is due to start on the £449m Brierley Hill to Wednesbury extension, which will feature 17 stops including Dudley Town Centre, Dudley Zoo, and the Black Country Living Museum, as well as an interchange at Dudley Port.
It is due to open in 2023.
The final piece of the jigsaw will see the Birmingham Eastside Extension move further eastwards by around 10.5 miles to serve North Solihull and terminate at the HS2 interchange station, allowing passenger access by Metro to the airport, National Exhibition Centre and Genting Arena.
West Midlands Mayor Andy Street has been a big advocate for the Metro since he took office in May 2017, believing it to be a central piece of a high level transit system that will connect the region like never before.
He says the benefits of it go way beyond better transport links, arguing that extensions bring new jobs and could even increase house prices along some routes. “For the last 20 years the Metro has given millions of passengers an excellent service between Wolverhampton and Birmingham, so it is only right to look back and congratulate everyone involved on this anniversary,” he said.
“However, we must also look to the future, especially as we continue work on trebling the network.
“Over the next few years we will have trams connecting new places including Dudley, Brierley Hill, Centenary Square, Hagley Road, Digbeth, Bordesley Green and Solihull.
“The first 20 years of the Midland Metro has been fantastic, but I hope the next 20 will be even better.”
Over the coming years, the network is set to triple in size under a £1.3bn investment programme, with Mr Street insistent that there will be no reliance on “handouts from Westminster” to fund the work.
“We will use our own resourcefulness to finance these Metro improvements,” Mr Street said in a recent mission statement on turning the West Midlands into what he calls a “world city-region”.
“We are leading the way in building a regional public transport network for the 21st century.”
Bosses say the extensions have largely been made possible by the decision to allow Transport for West Midlands (TfWM) to take over the day-to-day running of the Metro, meaning future profits can be ploughed directly into the network.
Director of operations Carl Williams said reaching 20 years was a “major milestone” for tram services in the region, and pointed to a bright future in the coming years.
He said the “serious work of massively growing the network” was gathering pace, and noted the importance of rising passenger numbers to the service’s success.
“We’ve a tremendously loyal customer base which is growing all the time and we’re looking forward to serving an even wider area over the years to come,” he added.
Today’s anniversary will see a specially liveried ‘Metro birthday tram’ make its way into service during the afternoon, while customers will be treated to on board entertainment, cupcakes and squeezy model trams for youngsters.
Customers boarding it before peak afternoon services will be able to join the party with singers from Birmingham Youth Theatre, a magician and a balloon modeller putting in an appearance on trips between Wolverhampton and Grand Central.
The Metro has not always been flavour of the month.
Six months of work along Bilston Road in Wolverhampton while new tracks were laid caused misery for traders, putting some out of business and leading to compensation calls that are yet to be fully resolved.
Businesses near to the Birmingham city centre extension are going through similar turmoil now.
And questions have been raised over the spiralling cost of the Brierley Hill to Wednesbury extension, which was initially quoted at £343m but is now expected to cost £449m.
Railways campaigners continue to argue that reopening disused rail tracks for trains is more cost effective than the Metro.
Phil Hewitt, West Midlands Metro director, said: “We’ve come a long way since 1999. We now have a new fleet of modern trams to which we’ll be adding even more as the network grows and we’re introducing the UK’s first stretch of overhead line-free track when the extension to Centenary Square opens at the end of the year.
“We’ve a great team of people proudly delivering services each and every day and it’s good for them to see that the Metro is going from strength to strength.”