And then there's the original purpose of the train station — trains.

The tracks are all still there. Freight trains roll by every day on their way to and from the Michigan Central Railway Tunnel under the Detroit River.

It could still function as a train station and create a direct link to Detroit Metropolitan Airport and the immaculate and seemingly underutilized John Dingell Transit Center on Michigan Avenue in Dearborn, which could be used for commuter rail to Detroit or Ann Arbor. The Dearborn bus and train station is just under two miles from Ford's Glass House headquarters.

Bringing trains back to Detroit's 105-year-old depot is an idea that Bill Ford said he'd "love" to see, but he noted it's "not really within our control."

"If we ever do get regional transit here, which I'm a big proponent of, you can image the AVs talking to the trains, talking to the buses and all of the transportation systems working together," Ford said. "In that respect, it would actually help our development if we had trains coming in."

Train service to the depot and autonomous shuttles that connect workers and visitors to downtown also would help fulfill Ford's promise that the renovated Michigan Central Station's concourse will be open to the public and that the hulking building won't become "a corporate island."

But bringing trains back to the train station is a whole different horse to tame that leads back to metro Detroit's long and fractious debate over mass transit.

Detroit Mayor Mike Duggan and Wayne County Executive Warren Evans have effectively hit a wall along Eight Mile Road in trying to get a regional transit tax and plan on the November ballot. Macomb County Executive Mark Hackel and his Oakland County counterpart, L. Brooks Patterson, are having none of what Evans and Duggan are proposing, and the Big Four leaders are arguably more divided than ever on this central economic challenge.

So now, with a major employer like Ford making big plans for developing future mobility solutions in Detroit, the time seems right for Wayne and Washtenaw counties to go it alone on a regional transit plan focused on fusing connections along Michigan Avenue and I-94.

The two counties could put separate transit millages on the ballot to fund expanded bus service and the long-sought Detroit-to-Ann Arbor commuter rail that could connect the talent pool at the University of Michigan with Ford CEO Jim Hackett's "knowledge cathedral" at Michigan Central Station.

Bus rapid transit along Michigan Avenue could connect U-M's research labs with autonomous vehicle testing at the American Center for Mobility at Willow Run, Ford's headquarters in Dearborn and the brain hub in Corktown, where Ford is making plans for up to 5,000 autonomous vehicle tech workers.

Commuter rail could bring the airport into the mix, helping fuel Wayne County's aerotropolis district and residential development along the I-94 and Michigan Avenue corridor.

Washtenaw County officials have signaled interest in teaming up with Wayne County, while Evans is still trying to salvage the Regional Transit Authority.

"That's the horse I'm riding, and I'm going to continue to ride it, because I still think it makes sense," Evans said in an interview. "I'm going to bet on the horse we rode this far. But if that doesn't go, I certainly am more than open to looking at the options."

Evans' horse is looking more and more like one that's not going to leave the stable.

MDOT's Steudle notes how it took a decade to plan, develop and build the QLine on Woodward Avenue, a project that was fueled by business leaders and the philanthropy of the Kresge Foundation as the streetcar was seen as a catalyst for redevelopment along the north-south corridor.

Ford's plans for linking Corktown to Dearborn could be a similar catalyst for redevelopment along Michigan Avenue, where the storefronts in southwest Detroit remain predominately blighted and boarded up.

"The challenge is, while four years is a long ways away, it really is a short time horizon for all of the pieces that have come together to make this happen," Steudle said. "You can't wait for two or three more years and then decide let's do something in the last year. You really gotta be talking about it now."