The final T69 tram that came into service in 1999 is being retired from service on Friday, as bosses move entirely to the new Spanish-built fleet.
Tram 16, which sports the original purple, red and yellow paint, will travel the 23-stop route from Wolverhampton St George's at 11.10 am, travelling to Birmingham Snow Hill before being commandeered by staff and taken to Wednesbury where it will be decommissioned.
The tram, named after Metro engineer Gerwyn John, was built in Italy by Ansaldo Breda, is the last one still in operation from the 16-strong fleet that went into service on the Midland Metro line between Snow Hill and Wolverhampton in 1999.
The old fleet has been gradually replaced over recent months as more of the 20 new Urbos 3 trams have arrived from Spanish manufacturer CAF.
It is a poignant moment for former Wolverhampton mayor Phil Bateman, who was instrumental in getting the Midland Metro brought to the Black Country in the first place.
He was serving as chairman of the passenger transport committee on the long-since-abolished West Midlands County Council in 1981 when the idea was put to the vote.
"That was when we said we saw the benefits of light rail and wanted a service for Birmingham and the Black Country.
"But it was another 18 years before we got it and it was opened.
"People think that was a long time, but it's been even longer since people were talking about road building with the Western Orbital Route - and we still don't have that."
Councillor Bateman, who was also the corporate affairs director for Travel West Midlands, now National Express West Midlands, which runs the Metro, said he proud to see the fleet being updated.
"I still can't believe we've even got the Metro, let alone gone the entire way through the fleet, maintaining and repairing it over so many years and now replacing them.
"It's testament to the engineers that they have had such a long and useful life.
"But these trams have been real workhorses too.
"Running a service every six minutes between Wolverhampton and Birmingham - they must have covered the equivalent of circling the globe several times."
Transport authority Centro and National Express will have a ceremony to send off the last tram on Friday, following its final public journey.
It will start its day at 6.04 am, from the Wednesbury depot, going to Snow Hill where it will start its service from 6.30 am.
The tram will then run the 23-stop 13-mile route a few times before making its last trip carrying passengers at 11.10 am.
The new Spanish built trams have not had the warmest of welcomes in the 12 months since they arrived.
Engineers have had to be flown in to fix a software glitch affecting air conditioning on the new fleet.
It emerged they were not programmed to cope with the fluctuating temperatures experienced in the UK.
Engineers are also seeking a permanent solution to remedy a failing set of doors on one tram.
The tram Gerwyn John was named after a Metro engineer who worked for the company from 1997 to 2003, when he left after becoming ill with cancer. He died the following year.
The old trams are just under 80 ft in length and can reach a maximum speed of 43.5 mph.
They weigh 38 tons and have space for 56 seats and 100 people standing.
Their Spanish replacements are more than 108 ft long and are slightly wider.
They also weigh 56 tons and have 54 seats, with space for 156 standing.