Those smaller programs would supplement some ambitious plans now under development by Miami-Dade transit and Florida East Coast Industries, the rail and real-estate empire founded by Henry Flagler, whose railroad along the state’s eastern shore marked the start of modern Florida and transformed Miami from backwater to metropolis.

The FEC, whose rail operations now focus on freight, stepped into the breach left by Gov. Rick Scott’s rejection of federal money for a planned high-speed rail line connecting Miami and Tampa via Orlando.

The company intends to invest $1 billion to reinstate passenger service from Miami along its existing line, recently refurbished to accommodate expanded cargo service to and from the Port of Miami, and to build a new spur from Cocoa Beach to Orlando. The All Aboard Florida passenger trains, though not high-speed rail, would run frequently and make stops in Fort Lauderdale and West Palm Beach, the FEC says.

Detailed engineering and ridership studies are now underway, and trains could start running as soon as 2014, FEC spokeswoman Christine Barney said.

“We think this will be transformative,’’ she said, noting that projections developed for high-speed rail concluded that more than 2 million people would use the service annually.

“We have seen nothing but enthusiasm for this idea. There is a great opportunity here for business travelers and families and other leisure travelers who really want to avoid highway congestion.’’

To maximize its appeal and usefulness, she said, the FEC also hopes to tie its new passenger line into existing mass transit at each stop.

Though precise end points have yet to be determined, the FEC owns several acres of vacant land around its downtown Miami spur. The county’s Metropolitan Planning Organization, responsible for transportation strategy, has been studying the possibility of a new multi-modal transit station in the area, which also includes the site of the demolished Miami Arena and the Overtown and Government Center Metrorail stations.

The linchpin of the county transit agency’s plans is the long-awaited, $500 million Metrorail airport link — the sole survivor of a series of heavy-rail extensions promised to voters when they approved a half-penny transportation surtax in 2002. Miami-Dade County officials eventually acknowledged that surtax revenue, much of which wound up subsidizing existing transit operations, was not enough to finance billions of dollars worth of Metrorail expansion.

Instead, the county opted to do what it could with surtax money, which provides the fiscal base for the city trolleys and other local transportation improvements. Funds also come from the Florida Department of Transportation, which put up $100 million of the money for the new Metrorail line to MIA, transit director Ysela Llort said.

That new elevated guideway links the existing Earlington Heights station with a gleaming, futuristic new Metrorail station at the Miami Intermodal Center, the partially completed “grand central station’’ of Miami known as the MIC, which connects to the adjacent airport via a short new PeopleMover ride.

With the new station’s upcoming inauguration, Metrorail will have two train lines: the new Orange Line, with trains going directly from Dadeland South along all existing stops to the MIC; and the existing line, rebaptized as the Green Line, with trains running from Dadeland South all the way to the Palmetto Expressway western terminus.

That means passengers wanting to travel between MIA and the Palmetto will change trains at Earlington Heights. Orange Line passengers will be able to reach MIA without changing trains.

That direct airport connection would also tie together downtown Miami and the MIC, which is slated to become a giant commuter hub.

A new station is under construction at the MIC for Tri-Rail, the commuter rail that runs to West Palm Beach.

Miami-Dade transit also plans to run BRT express buses — increasingly popular around the world as an alternative to costlier rail transit — from the MIC north along 27th Avenue, and west to Florida International University and beyond to Southwest 147 Avenue along 836 and Southwest Eighth Street. Those are routes county officials had once hoped to cover by Metrorail.

No budget has been developed, but the system would be financed with surtax and state money, Llort said.

Meanwhile, the agency has put new cars on the downtown Metromover and begun sprucing up its stations, installing new shade canopies and repairing long-broken escalators. The long-closed Bicentennial Park station will be refurbished and reopened in time for the art museum’s opening, and Swire will build an entirely new, cutting-edge station integrated into its CitiCentre project.

“Transportation changes the landscape of cities,’’ Llort said, “but you have to make these things convenient and attractive.’’