After 10 years of starts and stops on building a 25-mile passenger rail line from Charlotte to Mooresville, transportation planners have an idea that sounds too good to be true.

Under the proposal, which state DOT officials and others started selling hard this week, trains would start running in 2017, commuters would make it through rush hour faster than in a car, new development (and jobs) would be burgeoning around 10 stations and most taxpayers would be on the hook for a fraction of the project's cost.

If this vision sets off alarm bells, we understand. It does sound optimistic. Even so, the plan has promise and we hope the elected officials and other decision-makers who will decide its fate will give it a fair and thorough examination in the coming months. It surely needs exhaustive vetting, but at its best, it could create jobs, slow worsening traffic congestion and serve as a model for the kind of extraordinary regional cooperation that will be needed to solve this area's challenges for years to come.

About 150 elected officials and staff from north Mecklenburg and Iredell counties gathered for four hours Tuesday to learn about the plan. Here's how it would work: The Red Line, as it would be known, would cost $452 million (in 2018 dollars) to complete. The state would pay one-fourth of that ($113 million) and the Charlotte Area Transit System (CATS) would pay one-fourth.

The other half would be paid by special assessments and taxes paid by businesses and other commercial developments around the new stations. The thinking is that the rail line would spark new development ($4.9 billion worth in 30 years) and increase property values close to the line. Much of the higher property taxes generated from those higher values would be used to help pay for construction costs. Separately, area businesses, attracted by the new business opportunities, would agree to pay a fee that would help pay for the line. The higher taxes and the fees would each generate more than $100 million over six years or so, DOT officials say.

The Red Line would take 5,000 or more people off I-77 and other roads each day and, theoretically, spark economic development up and down the route, including in places that badly need it such as Derita and other parts of north Charlotte. With federal money for commuter rail dried up and the state and CATS pinched as well, the latest plan hatches some much-needed innovation. That's why elected boards in Charlotte, Huntersville, Cornelius, Davidson, Mooresville and Mecklenburg and Iredell counties should study the proposal, improve it and decide whether it deserves their support next spring.

They should also ask a lot of hard questions, including:

What if the anticipated development doesn't come, or comes very slowly?

What protections do taxpayers have, and how bulletproof are they, if the state has to temporarily step in to cover shortfalls?

How will CATS come up with $113 million without failing to meet many other transit demands around Charlotte?

How do you protect residents on a fixed income who see their property values, and thus their property taxes, balloon?

Residents and elected officials would be wise to reserve judgment. They would also be wise to see if they can responsibly pull off this major transportation and economic development plum.