Another summer with more big traffic jams on the way to Mount Desert Island, Bar Harbor and Acadia National Park. Since the pandemic, visits have soared to 4 million annually, mostly in July and August.

While some coastal locations seek more visitors amid the president’s war of words with Canada, MDI may have too many. It’s not a new problem.

In the 1990s, the National Park Service commissioned a bus service to ease the flow of visitors around the island. Back then, top-heavy RVs clogged park roads, making it hard to even see Sand Beach or Thunder Hole.

The solution was the free Island Explorer, which worked so well the National Park Service exported it to the Grand Canyon. Visitors leave their cars and campers and travel by bus. On-island circulation vastly improved, but mainland traffic has worsened. The Maine Department of Transportation’s solution was a park-and-ride at the Trenton welcome center, envisioned for a thousand vehicles.

That proved unwelcome and unaffordable, but a new 300-car lot opening soon will connect with the Island Explorer. It’s unlikely to make more than a dent in the weekend backups, however, which extend for miles.

Island traffic isn’t the only problem. It’s five hours of hard driving from Boston to Bar Harbor under ideal conditions, not considering peak-hour congestion, construction and accidents.

The breathtaking air and scenery of MDI seems worth it, though one wonders what the limit is. MaineDOT is clearly out of ideas, but there’s another one we haven’t properly considered: passenger trains with full-size buses.

In the 19th century, visitors reached Maine’s coast by train or boat. Then came the great automobile romance and demise of passenger trains; the last one left Portland in 1965.

Trains finally returned via the Downeaster from Boston to Portland in 2001, thanks to advocacy by businessman Wayne Davis, brokered by U.S. Senate Majority Leader George Mitchell, Amtrak President Graham Claytor and MaineDOT Commissioner Dana Connors. Service to Brunswick began in 2012.

Davis and Mitchell envisioned restoration to all Maine’s major cities, including Lewiston, Augusta, Waterville and Bangor. The advantages would be enormous. If trains stopped in Bangor, it’s a 40-minute bus ride to Bar Harbor. Travelers from Washington, New York and Boston (and Portland) could arrive car-free.

Yet MaineDOT and the Northern New England Passenger Rail Authority that runs the Downeaster insist new riders would be minimal and necessary investments would be pointless. Like any public issue, it depends on how you look at it.

I worked with rail advocates during the recent legislative session and learned all about how trains work in the 21st century. Worldwide, train travel is booming — in China, Europe and the U.S., with major new investments in high-speed rail in Florida and California, among other states.

Advocates hoped Maine would participate in a Biden-era corridor ID program allocating $66 billion for extending and reinforcing Amtrak routes, a record investment. Lawmakers said no, but they didn’t have all the facts.

A new study using different assumptions determined 260,000 passengers would ride trains to Bangor yearly, against 80,000 predicted by the DOT’s “propensity” study — those leaving their cars to ride a train between Portland and Bangor. Unfortunately, the new study arrived too late to influence most legislators’ votes.

But there are countless reasons to ride trains the new study captures. Congestion — there’s little north of Brunswick — isn’t the primary reason.

Expanded service would greatly increase the Downeaster’s current 600,000 passengers. Yes, it would take time and money, but — unlike highway expansion — the necessary rail is in place and new owner CSX has extensively upgraded track.

Everywhere train stations appear, development follows. Just look at downtown Brunswick. Portland’s Congress Street, now down at heel, will revive when plans to move the existing station downtown are fulfilled. Vacant storefronts fill up, van and bus services thrive and complaints about parking plummet. Compact, affordable housing becomes feasible downtown, and trains are by far the best way to reduce carbon emissions.

There’s a lot to like, and it’s not pie in the sky. A 2025 opinion survey reports 62% of Mainers would ride a Bangor train; an equal proportion say they’d vote for a bond issue to cover Maine’s share.

It didn’t happen this year, but with a new administration and new legislature arriving in 2026, the case for improved public transportation, including rail, can no longer be ignored.