SPRINGFIELD - A new report by backers of high-speed passenger rail service shows the fastest route between St. Louis and Chicago might run through Decatur.

The study, to be formally released today, is designed to jump-start talks on improving rail service at a time when the state and federal government are ready to pour billions of dollars into its development.

"We're trying to elevate the level of discussion," said Rick Harnisch of the Midwest High Speed Rail Association, which sponsored the study.

Illinois and California appear to be the frontrunners for an estimated $8 billion in stimulus money, based on guidelines issued last week by the U.S. Department of Transportation.

Gov. Pat Quinn is asking lawmakers to insert $400 million for high-speed rail in the long-awaited statewide construction program.

For years, high-speed rail development in Illinois has focused on the Amtrak route that connects Chicago and St. Louis with stops in Dwight, Pontiac, Normal and Lincoln.

But, most believe the trains on that route won't move faster than 125 miles per hour because of the frequency of freight traffic on the shared tracks, as well as scores of road crossings along the way.

A freight bottleneck near Joliet has been problematic for Amtrak scheduling for years.

Bumping the speed from a current maximum of 79 mph to 125 mph would cut the travel time from more than five hours to less than four.

But, some believe it should be even shorter.

Harnisch said planners should consider building a dedicated, European-style rail link that allows trains to travel at speeds of more than 225 mph, cutting travel times to close to two hours.

If such a project were given a green light, the study shows the route would connect St. Louis and Chicago via Springfield, Decatur and Champaign, Harnisch said.

Harnisch agrees such a plan might threaten high-speed rail supporters in Bloomington-Normal, which would be bypassed under the proposed new route.

"People in Bloomington need to tell their congresspersons that they want service," Harnisch said.

The rail association's study will be presented during events in Champaign, Decatur and Springfield today, said state Sen. Martin Sandoval, D-Cicero.

Sandoval, chairman of the Senate Transportation Committee, said the legislature will convene in Springfield today to put the final touches on the capital bill, which will include the $400 million for high-speed rail service.

"I've been a champion and advocate to make sure it will be funded by the Illinois legislature," said Sandoval, who has been the committee chairman since January. "I am putting the steam in the engine to make sure it becomes reality."

While Sandoval said he did not know how much the Chicago to St. Louis service would cost, he believes Illinois has a good chance of landing the necessary federal funding.

"President Obama has laid out $8 billion for high speed rail service throughout the country," Sandoval said. "Given that we are the transportation hub for the country, it is appropriate that Illinois leads in the vision that President Obama has for high-speed rail."

kurt.erickson@lee.net|789-0865