Here's how the freight rail strike will impact commuters

Washington, DC(CNN) US commuter rail service will face a huge disruption Friday if a freight rail strike is not avoided.

Many passenger rail services operate on tracks owned by freight railroads. Without the freight employees on hand to operate their networks, US rail commuters will be unable to make their trips. Some passenger rail operators have already cautioned customers about service disruptions. Amtrak faces the largest impact, as it generally only owns tracks between Boston and Washington, DC, but regional and local rail services will suffer as well.

Metra, which operates 11 commuter rail lines in the Chicago area, warned its customers in a statement Tuesday that "a potential work stoppage by freight railroad workers" could "directly impact" its "ability to operate most of its services."

"We want you to be aware of this issue so that you can make alternate plans for travel should a work stoppage occur," Metra told customers.

Metra's 11 rail lines carried an average of 36 million passengers annually from 2019 to 2021, but only two of those lines are wholly owned by Metra and would remain in operation amid a freight strike, according to spokeswoman Meg Reile. She said Metra was in talks with the railroads to see if an additional line could remain active if Metra assumes responsibilities for controlling traffic on the tracks, a duty currently held by a freight railroad.

"It's all up in the air," Reile said. "We don't have any clear answers yet."

The San Joaquin Regional Rail Commission, which operates the Altamont Commuter Express in California almost entirely on Union Pacific Railroad tracks between Stockton and San Jose, expects to reduce service Thursday and fully suspend it Friday.

"As you can imagine, we are watching the situation very closely," its marketing manager David Lipari told CNN Business.

The Maryland Transportation Authority, which operates the MARC train on CSX tracks with about 250,000 monthly riders in the Baltimore-Washington area, warned riders Monday afternoon that its Camden and Brunswick lines will be suspended until a resolution to the potential strike. The agency's commuter buses will honor MARC tickets during the service disruption. Its Penn line will remain active as the tracks are owned by Amtrak.

Many parties are hopeful that a strike will be averted. The White House has pushed for a resolution. Freight railroads reached for comment declined to detail any steps that they may take to allow passenger operators to remain in service.

There are some passenger rail exceptions that will not be impacted by the strike.

The Metropolitan Transportation Authority, which operates the Metro-North Railroad and Long Island Rail Road in New York that have carried roughly 146,000 passengers a day this month, does not expect any impact. It has its own staff that operates the trains and owns most of the tracks the lines operates on.

But others aren't as well-positioned for a strike.

Freight railroad BNSF operates Sound Transit's Sounder trains in Washington state. Sound Transit spokesman David Jackson said his agency is looking at options to support customers if there's no service.

BNSF said in an emailed statement it would work with agencies to avoid disruptions and minimize impacts, but declined to provide any details about how it's doing so.