America is already feeling the consequences of a looming nationwide rail strike

America's freight railroads have already stopped accepting shipments of hazardous and other security-sensitive materials because of the looming threat of a strike Friday.

Union Pacific, one of the major national railroads whose operations would be halted by a strike, said the move is meant to "protect employees, customers, and the communities we serve."

A statement from the railroad's trade group said they needed to take this step in order to follow federal rules to "ensure that no such cargo is left on an unattended or unsecured train."

But the unions...