Freight rail strike could start Friday if deal isn't reached with unions representing workers

PHILADELPHIA (CBS) -- A looming freight rail strike could start Friday and cause massive supply chain disruptions. Nearly 30% of all U.S. freight shipments could be halted if the nation's railroads can't cut a deal with unions representing about 60,000 workers.

The two sides are at odds over sick time and attendance policies. 

The White House is hosting a meeting with railroad and union officials in an effort to avert the strike. 

Federal law actually allows Congress to step in and prevent railway workers from striking, but democratic leaders say they are not going to go down that road. 

Amtrak is pre-emptively canceling long-haul service on impacted tracks.