One of the city's most-heralded grassroots street transformations is about to undergo another massive overhaul.

Packaged in Tuesday's $1 billion light rail transit announcement was the news that a spur line on James Street North is also in the works to connect the main transit corridor on King Street with the new GO Station.

That means an area that has undergone a years-long, arts-focused renaissance will start to look completely different in 2019 when construction starts.

James Street's stalwarts are excited, but with one condition — the city and the province need to make sure they get it right, and don't erase the progress that's been made already. The biggest issue: making sure the line isn't just for GO access, but serves the street itself.

It might not be the most welcoming place for a little while, but we have to look at Hamilton in the long term. - Dave Kuruc, owner, Mixed Media

"This is drastically going to change the face of the street," said Dave Kuruc, who runs Mixed Media on the corner of James and Cannon. "But it's a huge opportunity."

The James Street spur line of the LRT system has actually been on the table since January, when Mayor Fred Eisenberger met with Premier Kathleen Wynne. The two parties discussed the connection to an east-west LRT line that day, Eisenberger told CBC News, when the province made it clear it wanted local LRT systems to be integrated with the regional GO service. Creating that connection came at the cost of shortening the length of the east-west line to stay within budget.

Eisenberger, who is a staunch LRT advocate, is unsurprisingly excited about what a north-south line could mean for James North — and eventually the waterfront. "To evolve a complete street on the James Street Corridor is a glorious opportunity," he said.

What will this thing actually look like?

But many questions about what the line will physically look like still remain. How many lanes will it take up? Will there still be car traffic on James North? Will the road need to be widened? Would a one track line be enough?

Metrolinx rebuffed questions on the specific design, saying it is too early to properly answer them. "An environmental assessment needs to be done first which will explore all those design questions," spokesperson Anne Marie Aikins said.

The economic outlook here I think would be fantastic. - Chris Higgins, McMaster University

Eisenberger also couldn't go into specifics, but said ideally, he'd like to see a space that is still pedestrian friendly, and includes bike lanes. It will likely be about a year and a half until we start seeing fine tuned aspects of the plan, he said.

He does expect, however, a dedicated LRT lane. "But it's not a carved in stone approach," he said.

But McMaster PhD student Chris Higgins – who lives in the James North area – says ideally, he'd like to see a streetcar-like approach on James North similar to what's used on King Street in Toronto.

That would be a mixed-use street with an LRT vehicle that makes stops along the way, alongside vehicular traffic.

"The economic outlook here I think would be fantastic," said Higgins, who was part of a study on light rail's economic impacts with the McMaster Institute for Transportation and Logistics. "You just have to do it properly."

Unlikely that cars would disappear

It's unlikely that planners would designate the James North spur purely for pedestrian traffic and an LRT system, Higgins said, as the new GO station on James would still need to be accessible by car.

Also, some cities like Calgary that have adopted that model in some areas are now moving away from it, he added. "But you can overcome those issues with proper planning," he said.

A lengthy construction process will no doubt take a toll on some businesses on the street. "I think you have to be prepared for that," Kuric said at Mixed Media. "But it all depends on how you promote it to your customers."

The upside on James North, Kuruc says, is that so much of the existing customer base for those businesses is walk up traffic anyway. "Our customers will find a way," he said.

"It might not be the most welcoming place for a little while, but we have to look at Hamilton in the long term," he said.

The most important thing about the planning process, Higgins says, it just ensuring that when installing LRT, the things that are working on James North like its focus on culture and pedestrian-friendly spaces aren't removed.

"To take those things away to have LRT would be like shooting yourself in the foot a little bit."

adam.carter@cbc.ca | @AdamCarterCBC