B.C. will contribute $300,000 to a Washington state business case study into the feasibility of a high-speed rail line connecting Vancouver, Seattle and Portland.
Premier John Horgan made the announcement alongside Washington Gov. Jay Inslee in Vancouver on Friday.
Washington state legislators already committed $1.2 million US ($1.6 million) to the analysis earlier this month.
Horgan called B.C.'s decision to contribute "a first step and ... a positive step" toward making the rail dream a reality.
"This is an opportunity we shouldn't let pass by," he said.
"There are opportunities for us to learn from best practices around the world ... and the study will confirm concerns or suspicions."
For the better part of a decade, politicians, business leaders and residents from both sides of the border have pitched and campaigned for the high-speed rail.
Advocates have said the trains would be capable of running up to 400 km/h up and down the Cascadia coast, reducing travel times and congestion. Others have said it would help businesses operating on both sides of the border.
"The convenience of a one-hour trip between Vancouver and Seattle would create countless opportunities for people in both B.C. and Washington, from sports or concert getaways for families, to untold economic growth potential for businesses," Horgan said in a statement.
Another study, presented in December, looked at which types of trains that could be used, possible routes, ridership forecasts and estimated costs.
It found the line could cost as much as $42 billion — largely depending on the type of train used — and that it could take decades to recover the cost.
The B.C. Transportation Ministry said it supported Washington's work to investigate the project, participating in an advisory role, but did not say if the province would be willing to help pay for that study.
Chuck DeVore, a former politician in California, has been a critic of proposed high-speed rail lines in the United States — including one over-budget, behind-schedule link currently being built between Los Angeles and San Francisco.
He called such links "an idealogical premise married to a crony corporate agenda" that should make taxpayers wary.
"What I would be most interested in are the sources of funding for the project," he said in reaction to Friday's announcement. "Do they require big tax increases in British Columbia and Washington state? Those are questions I would ask, before I would want to see any project move forward.
"Buyer beware: the taxpayer is likely going to come out of this with less money than they went in."
DeVore also questioned whether or not a railway is the best option to connect Cascadia.
"The challenge with high-speed rail is that it is based on a very old technology: point-to-point fixed rail. The challenge is, is this really what we want to be investing our money on, in this day and age, where you have so many other options for transportation."
Inslee said the study will be finished by summer 2019.
With files from Greg Rasmussen