The rail unions are headed toward a strike over pay and ongoing grievances from members that the working conditions are grueling, and not conducive to a life off the job. With a Dec. 9 deadline looming, Congress reluctantly inserted itself in the middle of the labor dispute this week to stave off a strike that would cost the economy $2 billion every day. But the unions have since rejected the deal and are poised to escalate the disagreement.

What this means: Much of the country's goods still travel by freight train. Ahead of the holiday season, a halting in the shipment of food products, and other critical goods could debilitate the economy.

What rail workers want: The railroad unions are asking freight and railway companies for a pay increase, as well as better working conditions, including paid time off and a more flexible schedule. 

Congress took "urgent action" to quell a strike: At Biden's urging, the House overwhelmingly passed legislation this week that would adopt a tentative deal reached in September between union leaders and freight operators. Unions representing rail workers have since rejected the deal, setting up the impending work stoppage.