Victoria Bridge was built in 1859. ((Photo courtesy of Transport Quebec))

Montreal's Victoria Bridge, considered an engineering marvel that spawned the island's modern industrial development, is celebrating its 150th anniversary this month.

The three-kilometre bridge was the first structure to span the St. Lawrence River and connect Montreal to the South Shore by railroad, opening the city to eastern and western seaports.

On Thursday, the bridge marked the 150th anniversary of its first passenger train trip, which took off from Montreal on Dec. 17, 1859. A freight train tested the tracks earlier that week.

'It's 150 years old, and it's still working. It makes modern technical things [look] maybe not quite as good.' —Sam Allison, retired history teacher

Quebec history buffs say the bridge played a pivotal role in Montreal's economic development.

"The Victoria Bridge brought us modernity," said Sam Allison, a retired history teacher who once taught at Centennial High School in Longueuil.

Before the bridge was built, the St. Lawrence was a daunting body of water to cross. Travelling to the South Shore from Montreal was done by boat in the summer and sleds in the winter, but only when the ice froze solid.

That meant "people couldn't leave the island very easily from December to May," Allison said in a recent interview with CBC. "It was much too dangerous. This meant we were isolated."

At the time, the Grand Trunk Railroad ended on the South Shore, which meant all goods had to be brought to and from Montreal by ferry.

The Victoria Bridge assured year-round transportation and access to seaports in the Maritimes, Toronto and Chicago, allowing Montreal to expand its business interests from furs and whiskey to other industries such as flour and sugar, Allison said.

The bridge was also a feat of engineering ingenuity that has stood the test of time, the retired teacher said.

"It's 150 years old, and it's still working. It makes modern technical things [look] maybe not quite as good."

Victoria Bridge built before the invention of steel

Building a bridge of that size at that time — about a decade before the invention of steel —  presented many technical challenges, said Hugh McQueen, a Concordia University emeritus professor of engineering.

"People had been trying to build bridges out of cast iron, which was cheap and available, but they kept breaking!" McQueen said in a recent interview. "There were several disasters in England. So they had to turn to a form of iron that is very ductile ... wrought iron, meaning hammered iron."

McQueen, who is giving public lectures on the bridge's 150th anniversary, has spent years poring over an illustrated lithograph copy of the span's engineering plans.

The bridge spawned ingenious innovations in construction techniques, McQueen said. The stone piers were angled at 45 degrees into the current to act as a long line of icebreakers. 

The builders also devised the first derricks to lift up the rocks brought in by barge and the first steam-driven cranes.

There was even a just-in-time delivery system for the prefabricated parts shipped from Liverpool, England, that used a fleet of steamboats.

The bridge was officially inaugurated by the Prince of Wales in August 1860.

The structure now accommodates motorized vehicles that use two iron-girded lanes flanking the railroad tracks.