Update:Strike Averted -- "Amtrak and nine of its unions have reached a tentative contract agreement, according to industry experts, and plan to announce the settlement on Friday."
A possible strike by Amtrak workers on January 30 would stop commuter rail service in the San Francisco Bay Area as well commuter rail service in the areas around Chicago, New York City, Boston, Virginia, Connecticut, the District of Columbia, Maryland, and Philadelphia. Thank you to Jennifer for the heads up.
Associated Press lists commuter rail services that would be impacted by an Amtrak strike. Chicago Metra, Long Island Rail Road, Southeastern Pennsylvania Transportation Authority, Maryland MARC, Virginia Railway Express, Connecticut Shore Line East, and San Francisco Bay Area Caltrain are either operated by Amtrak employees or use facilities controlled by Amtrak and would be impacted by the strike.