The region’s best hope for rail transit just put on some rubber tires.

In the first detailed look at the plan being pitched by Jackson County Executive Mike Sanders, consultants have determined that rail service should be explored immediately on only two of the six routes proposed between downtown and the suburbs.

The preliminary findings mean that some routes — including proposed lines to Liberty, Grandview and Kansas City International Airport — could begin as express bus lines.

“In no way does that mean to indicate that rail isn’t a long-term, viable strategy in any one of these corridors. It will still be on the table. There’s just more work to do,” said Tom Gerend, assistant director of transportation at the Mid-America Regional Council.

Commuter rail differs from light rail in that it typically goes longer distances, from downtowns to suburban areas. Stations are farther apart, and sometimes commuter and freight trains share the same track.

The most promising commuter rail routes for now are to Independence and Blue Springs, along I-70, and to Lee’s Summit paralleling Missouri 350.

Those routes, using underused or abandoned rail corridors, are among the least expensive and are projected to attract more riders than the other routes in Sanders’ plan, which he has dubbed “Regional Rapid Rail.”

Planners are seeking federal funds for a more detailed study of those two corridors — a required first step if the area hopes to land federal money for a regional rail system.

They will also study the use of modern streetcars in the Main Street corridor, which has been studied before for rail.

Normally, such studies can take years before they produce an award of federal money.

“It’s not something that one snaps their fingers and says, ‘Here we go. Let’s build it now,’?” said consultant Mark Kenneally of the TranSystems planning firm.

The 135-mile network of commuter rail lines would radiate from Union Station and cost an estimated $1.2 billion to construct. That’s about $200 million more than the first plan unveiled to the public.

The latest study, costing $150,000, was commissioned by the Mid-America Regional Council. After a competitive selection process, the study went to TranSystems, which had designed Sanders’ plan.

Sanders, who has presented his vision for rail in briefings and presentations across the area, said the results are not too surprising or alarming.

“You’ve got to know which ones are the best routes to study,” he said, citing the area’s limited budget to pay for the studies.

“We’re taking the ones that at first blush look like they’d have the best ridership, the ones that would have the most bang for the buck.”

But that doesn’t mean that the other routes couldn’t someday feature rail service.

“Ultimately, we’re going to need to study and deal with issues in all these transit corridors,” Sanders said. “But we have to start somewhere.”

Nor did the preliminary results surprise some transit advocates.

The four lines to Liberty, the airport, Wyandotte County and Grandview “can’t be justified in the near term,” Janet Rogers of the Transit Action Network recently wrote to supporters.

“This isn’t really surprising. Each line has different issues, but they don’t generate enough ridership to warrant the expense at his point.”

Rogers backs going ahead with the study of the two remaining lines.

“Many people in eastern Jackson County have been pushing for rail for a long time,” she wrote in her e-mail.

But she wonders about the future of commuter rail.

“Kansas City needs a comprehensive transit system, but since four of the six commuter routes originally envisioned by the plan are not being pursued at this point, this may not be the solution,” she said.

Planners at MARC stressed that their study doesn’t stop here. They want to continue to evaluate all six corridors for different types of mass transportation — including buses — in the future.

Sanders said he hopes that rail can be in place more quickly than the normal federal timeline would dictate. But the region won’t be prepared to act on any new appropriations if it doesn’t begin that federal process.

Commuter rail, he added, is but a piece of the area’s transit puzzle. Streetcars, light rail, bus rapid transit and other buses will need to be part of an overall plan.

The consultants pinpointed short-term deficiencies of the commuter rail plan, including:

•Preliminary traffic models show that in many cases, traveling by car in 30 years would still be as fast or faster than taking a commuter train from the suburbs into downtown.

•About 36 percent of the land needed for the entire plan still needs to be bought. Extensive land purchases would be required along U.S. 71 to Grandview and along Interstate 29 to the airport.

•Some areas that would be served with rail suffer from low concentrations of people, namely the route along I-35 to Liberty.

The most recognized supporter of light rail in Kansas City — Clay Chastain — continues to push for his latest plan for rail transit. The main difference between the two is that Chastain’s plan contains a light rail spine that cuts down the Main Street corridor to KCI.

At a recent meeting of the board of the Kansas City Area Transportation Authority, Chastain proposed merging elements of his plan with Sanders’ plan.

“Everyone says, ‘Why can’t we get together and fuse elements of these plans?’?” Chastain said.

In a statement, Sanders’ top aide, Calvin Williford, said the county is working on a regional solution in accordance with federal rules.

“We’ve yet to see from Mr. Chastain any attempt to comply with federal funding guidelines and criteria,” Williford said. “There’s no connection between what we’re doing and what he’s doing.”

The new MARC-led study of the two most promising commuter routes, which could take a year or two, also will include a look at streetcars — which are slower and less costly than traditional light rail — in the Main Street corridor.

Sanders said he supports this because commuter rail passengers will have to get from Union Station to other key locations in the central city.

He noted that the recent award of federal transit funds to several other cities for new streetcar lines is more evidence that Kansas City must push forward on transit.

“We’ve got to position ourselves so that there are no longer dollars going everywhere but here,” he said.