One of the big splashes at the North American International Show preview next week may not have anything to do with road-bound vehicles.

I'm hearing scuttlebutt that U.S. Department of Transportation Secretary Ray LaHood will announce during the auto show a long-awaited $25 million federal grant for the streetcar line proposed by a public-private group for Detroit's Woodward Avenue.

LaHood, who has visited the auto show in the past during the media previews and is expected again this year, has said for some time that the grant for the M1 Rail project was contingent upon Michigan approving a regional transit authority law for metro Detroit — legislation that was signed by Gov. Rick Snyder earlier this month.

His office isn't saying much. Neither is M1 Rail. But the gathering of thousands of journalist and prominent VIPs at Cobo Center provides the perfect venue for such an announcement.

Whether he would announce the grant during his tour of the show floor, or return later in the week for a formal announcement, isn't clear.

The rail consortium has long sought the $25 million as part of its estimated $137 million to build the 3.4-mile line on Woodward Avenue.

The rest of the capital funding is coming from private donors, foundations, corporations, federal tax credits and a commercial loan. The operational funding plan is a mixture of fare box revenue, grants, and advertising and naming rights sales.

M1 has said since its 2007 formation that it intends to get itself up and running, including its own funding, before turning itself over to an RTA.

The regional transit authority won't actually oversee Woodward rail. Instead it'll oversee a proposed $500 million, 110-mile rapid-transit regional bus system with 23 stops that would operate much like a rail line, using specialized, train-like buses with dedicated lanes. The buses would run along Gratiot, Woodward and Michigan avenues and M-59 and would connect to Ann Arbor and Detroit Metropolitan Airport in Romulus.

For the RTA to assume oversight of a rail system, a unanimous vote of the 10-member RTA board is required, followed by a referendum in the authority's four-county area — one of the major criticisms of the RTA bills.

LaHood said in June that M1 wouldn't receive a previously earmarked $25 million grant, which was subsequently allocated to the Detroit Department of Transportation via the state.

Instead, LaHood promised another $25 million for M1 if the state created and approved an RTA, and also answered operational and funding questions he had about the streetcar project.

It's not immediately clear whether the questions were satisfactorily answered or not.

LaHood did direct the Federal Transit Administration to begin the required environmental approval process for the project.

In April, M1 submitted a 1,200-page report in April to LaHood's office, meeting a requirement he had set for the group on Jan. 6 to validate its project — and its costs — before it could be eligible for federal aid.

That report apparently didn't satisfy federal concerns.

The 3.3-mile line between Hart Plaza and New Center (with a predicted 3 million yearly users) will cost only $5.1 million annually to operate, rising to $6.5 million by 2022, according to M1's report to Washington.

M1 has said it will endow a $10 million fund to operate and maintain the system for up to 10 years, until 2025, at which point the group plans to donate the project assets and operating responsibility to a public agency, such as the proposed regional transit authority.

M1's plan is a mostly curbside-running, fixed- rail streetcar circulator system, co-mingled with traffic, with 11 stops between Grand Boulevard and Congress Street. It will run in the median at its north and south ends.

The leadership of M1 Rail is Penske Corp. founder Roger Penske; Peter Karmanos Jr., founder of Detroit-based Compuware Corp.; the Ilitch family, owners of the Detroit Tigers, Red Wings and Little Caesar Enterprises Inc.; and Quicken Loans Inc. founder Dan Gilbert, the project's other co-chairman.

Major commitments of $3 million have been secured from Quicken Loans, the Ilitch companies, Penske Corp., Compuware, Chevrolet, Blue Cross Blue Shield of Michigan, the Detroit Medical Center, Wayne State University, Henry Ford Health System, Wayne County, the Ford Foundation and the W.K. Kellogg Foundation. The Hudson Webber Foundation has pledged $1 million.

The $3 million commitments are for the display advertising rights to a station along the route. The Troy-based Kresge Foundation has pledged $35.1 million, part of which already has been spent, and it gave an additional $3 million as a "backstop" grant.

The Detroit Downtown Development Authority has earmarked $9 million for M1. An additional $16 million is from federal New Market Tax Credits, which have to be reapplied for annually. Financing plans include a $22 million commercial loan.