CHICAGO (CBS) — Some commuters will have to make alternate plans during the NATO Summit, as Metra today said it will close several stations on the Electric Line.

All Metra passengers–not just those on the Electric Line–will also face carry-on restrictions and security screenings from May 19-21. Riders will be allowed one briefcase-sized bag up to 15 by 15 inches and four inches deep. Riders will not be allowed to carry boxes, luggage, backpacks, pocket knives, bikes, food or liquid. This includes all beverages, such as coffee and soda.

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Stations on the Electric Line that will be closed May 19 and 20: Museum Campus, 18th Street, McCormick Place, 27th Street and Kenwood.

More stations will close on Monday, May 21:

• On the main line, trains will not stop at 111th Street (Pullman), 107th Street, 103rd Street (Rosemoor), 95th Street (Chicago State University), 91st Street (Chesterfield), 87th Street (Woodruff), 83rd Street (Avalon Park), 79th Street (Chatham), 75th Street (Grand Crossing), 63rd Street, 47th Street (Kenwood), 27th Street, McCormick Place, 18th Street and Museum Campus/11th Street.
• On the South Chicago branch, trains will not stop at 87th Street, Cheltenham (79th Street), Windsor Park and Bryn Mawr.
• Trains will not operate on the Blue Island branch.

READ: Metra Revised Electric Line Schedule
READ: Metra Passenger Checklist

The other line that runs under McCormick Place–the South Shore from Indiana–has not yet announced its plans.

One thing is clear, passengers who pass through McCormick during the summit will face closer scrutiny, CBS 2′s Susanna Song reports.

Several dozen commuter trains run underneath McCormick Place.

Metra Electric and South Shore passengers who ride these lines will most likely face delays.

Commuters can expect to be screened and their trains to be searched before boarding.

Even though they won’t admit it, Metra officials had to fight hard to limit the inconvenience to its riders, at one point balking when the feds wanted them to stop all trains short of McCormick Place.

“This has been a process that looked at everything including stopping the trains,” Metra CEO Alex Clifford said.

Theresa Peterson, a South Shore line passenger said her conductor has already hinted at these extra security measures.

“They have told us they are going to have bomb sniffing dogs, wands .. and the TSA will be here. They have been upfront,” she said.

During the two- day summit, 60 South Shore line trains and more than 200 Metra trains will be impacted.

Parking restrictions around McCormick Place start this weekend, with major road closures–including I-55 and Lake Shore Drive will go into effect the day before and during the summit, May 19-21.