freight railroad strike, and the economic upheaval it could cause, is getting closer and closer to reality.

While two more rail unions reached tentative agreements with railroad management on new contracts Tuesday, the two most important unions — representing the engineers and conductors who make up the two-person crews on each train — remain at loggerheads in negotiations. If they don't resolve their differences, the first national rail strike in 30 years could start early Friday.

Those engineers and conductors unions represent roughly half of the more than 100,000 unionized workers at the nation's major freight railroads. Without them on the job those trains will not run, nor will many commuter and Amtrak trains that run over freight rail lines. Indeed, Amtrak has already suspended some of its routes.

Unable to reach a deal Tuesday, the heads of the two unions and the negotiators for the railroads' bargaining team are scheduled to meet with Labor Secretary Martin Walsh in Washington early Wednesday, according officials with each union and a Department of Labor spokesperson.... Read More: CNN