A plan to remake Austin’s transit system over the next two decades could cost as much as $9.8 billion, according to initial cost estimates released Tuesday. That most expensive option would build two light rail lines, one running along a north-south axis, and the other connecting Austin-Bergstrom International Airport to downtown.

Local officials would seek to cover 40% of the cost from federal grants and pay for the rest likely by borrowing money through issuing bonds.

The estimates come from initial engineering studies conducted by Capital Metro this year as part of its ambitious Project Connect plan that will likely figure heavily into a transit bond in 2020.

Capital Metro staffers will present the figures Wednesday at a joint meeting of the Capital Metro board and the Austin City Council. The council holds heavy influence over how much of Cap Metro’s transit plan will see the light of day.

"What we wanted to do was to give the potentials for what the system could be, what the ridership could be, what the potential cost could be so that everybody has that information to consider going forward," said Dave Couch, Capital Metro’s manager for Project Connect. "Exactly what that local funding is and how it is handled, and in which direction is something that comes in a further step.

A large majority of Cap Metro’s estimated costs for Project Connect are for the proposed Orange and Blue lines — rail or bus rapid transit lines that appear to combine elements from the last two rail proposals defeated by voters in 2014 and 2000.

The Orange Line would run along North Lamar Boulevard and Guadalupe Street, through downtown and along South Congress Avenue.

The Blue Line would run from Austin Community College’s Highland campus in Central Austin, through downtown, crossing Lady Bird Lake possibly on a new bridge, to East Riverside Drive and then east to Austin-Bergstrom International Airport.

Parts of those lines could be elevated and in tunnels possibly in or near downtown, according to the presentation of the plans.

Other elements of the plan include a commuter rail line on existing tracks to Manor and additional MetroRapid bus routes.

Even the low-end cost of $2.8 billion for the entire system that could be footed by local taxpayers dwarfs the $600 million starter rail proposed in 2014 and the $970 million rail line voters narrowly defeated in 2000.

Cap Metro estimates between 45,000 and 74,000 people could ride the Orange Line each day by 2040. The end-to-end travel times from the Tech Ridge Park and Ride to Slaughter Lane are estimated at 42-53 minutes.

For the Blue Line, the transit agency estimated between 30,000 and 52,000 passengers could use the transit line daily. End-to-end travel times would be 35-45 minutes.

Rail would allow for more passengers. However, they come at a greater cost per rider. Rail lines also would take longer to construct, the presentation states.

The City Council and Cap Metro’s board likely will decide on the scope of the plan, including rail or buses on the Orange and Blue lines, in January when they meet jointly again.

"Our process right now ... is to look at what the technical ability is, what the potentials are and how we can go ahead to come up with the best and the most efficient transit system for Austin," Couch said.

But the City Council will have the ultimate power to decide what will be put to voters. Council members likely will make that decision in March, according to a timeline in the presentation.

That would then be placed on the ballot in November 2020, a presidential election with expected high turnout.