Politicians have been trying to restore and repaint a historic Quebec City bridge, known as the Pont de Québec, for nearly a quarter of its 97 years of existence.

Its almost identical twin in Edinburgh, Scotland, on the other hand, is sporting a new paint job.

The bridges in Quebec City and Edinburgh are virtually carbon copies of each other. They were both built on the turn of the 20th century by the same engineers, following very similar designs.

But, the Forth Bridge in Edinburgh now has something that sets it apart — a triple coat of paint, meant to last at least 25 years.

Meanwhile, the Pont de Québec, which links Quebec City to Lévis, is rusting over the St. Lawrence River.

The bridge that's been through a lot

The Pont de Québec is one of the city's icons. The riveted steel truss structure was built in 1919 and is still the longest cantilever road bridge. It's also a National Historic Site of Canada.

The bridge is also the site of the city's most significant tragedy — 88 workers died when the bridge collapsed twice during its construction.

Gilles Lehoullier and Régis Lebeaume

Gilles Lehoullier, the mayor of Lévis, and Quebec City mayor Régis Lebeaume, said in 2014 they will not let the Pont de Québec rot. (Radio-Canada)

The effort to paint the now-rusting bridge has become another chapter in its long history.

In 1993, the federal and provincial governments and the bridge's owner, CN Rail, put $60 million together to paint it.

But CN only painted a third of the structure before the money ran out. It abandoned the project in 2005, leaving the bridge two different colours.

A decade later, Quebec City's mayor led a seemingly inexhaustible campaign to restore it, despite an estimated cost of up to $400 million.

In 2014, Mayor Régis Labeaume penned a curtly worded letter to CN's principal shareholder — billionaire Bill Gates.

Forth bridge in Edinburgh

The Forth Bridge in Edinburgh, Scotland is very similar to the Pont de Québec in Quebec City. (John Andrew, Balfour Beatty co.)

About 150 people gathered near the bridge one month later. The bridge spurred other local initiatives including one shop owner selling bridge T-shirts and another resident made a video with her children, pleading for Gates to paint the bridge.

The city draped a "Paint Your Bridge, Bill" banner in the backdrop for the group photo that was later sent to CN.

The mayors of Quebec City and nearby Lévis even bought stock in CN, with plans to confront the company at a Memphis, Tenn. shareholders' meeting. They later nixed that idea.

Like painting the Forth Bridge

 One of the engineers who orchestrated the Scottish project says resuscitating the Forth Bridge was also a struggle.

"It's not about a pot of paint, that's the simple bit," said John Andrew, business development director with British construction company Balfour Beatty. 

People used to say they saw pieces of the bridge falling into the water, although it was actually the paint that was falling off, he said.

"For a neverending job in the U.K., we [say] 'It's like painting the Forth Bridge'," he said.

The bridge was finally repainted in 2011. Andrew said "challenge" is the best word to describe the undertaking.  

"You've got to get people onto the bridge safely, you've got to do the repair work safely," he said. "You've got to strip all the existing paint from the bridge safely without contaminating the environment and especially the waters below. And then you've got to paint the paint on it as well."

The real secret to accomplishing the work, he says, is to foster a love for the bridge. The Forth Bridge is a UNESCO World Heritage site, and was just voted Scotland's greatest man-made wonder.

"Scotland loves this bridge," Andrew said. "If you don't maintain something and it goes into disrepair, the public is not going to be with you."

with files from Glenn Wanamaker