Call it a landlord-tenant dispute that’s gone slightly off the rails. It’s Amtrak vs. Metra and, luckily for Chicago commuters, eviction is not an option.

Amtrak, owner of Union Station, has asked the federal Surface Transportation Board to settle how much Metra should pay for continued access to the terminal. The lease agreement, dating from 1984, is due to expire Monday, July 29, and Amtrak said talks are at an impasse.

But no one will be barring commuter access or tearing up tracks, said Amtrak spokesman Marc Magliari. “There will be no interruption of Metra’s usage within the station. Customers will see absolutely no differences,” he said.

Metra now pays Amtrak, the national passenger railroad, about $9.66 million in annual rent. The dispute involves how that figure might change and how to divide the costs of capital improvements when Metra accounts for the vast majority of people passing through the terminal.

The transportation board is involved because it decides disputes among railroads. Magliari would not say how much Amtrak wants in rent but noted that since the lease originated, Metra’s use of Union Station has risen 40 percent.

One source said Metra wants to lower its annual rent to about $7 million.

In a petition to the board dated July 22, Amtrak said, “Despite protracted negotiations ongoing for more than a year, the parties cannot come to an agreement regarding operating and maintenance cost-sharing, an infrastructure recapitalization arrangement, or the terms of the contract.”

It further said that its renewal proposal to Metra avoids any cross-subsidy of inter-city passenger and commuter rail systems that federal law prohibits. It has proposed Metra pay all costs for improvements that benefit Metra only, and a portion of the costs that benefit Amtrak and Metra.

Amtrak said the proposal “includes fair, adequate, and reasonable terms that allows Metra to continue to access and use Chicago Union Station in a manner that is equitable to both Metra and Amtrak.”

Metra spokesman Mike Gillis said in an email: “Metra is seeking the best deal for its customers and for the taxpayers of northeastern Illinois. We agree that requesting the involvement of the Surface Transportation Board at this juncture is appropriate and we look forward to making our case there.”

The transportation board had no immediate comment about a timetable for settling the issue. The board includes former Chicago Ald. Martin Oberman, who previously was Metra’s chairman. President Donald Trump appointed Oberman to a seat reserved for a Democrat.

Metra sent 38.1 million passengers through Union Station in 2018, making it the third busiest rail hub nationwide, Amtrak said. Amtrak accounted for 3.3 million passengers at Union Station last year, it said.

Magliari said the dispute has no impact on plans to add a hotel to Union Station and an office tower near it.