Sunday's CBS-TV show, "60 Minutes" will be on the New York City Subway system

-- "Inside the century-old parts of the New York City subway"

New York City's vast subway system is an iconic piece of American infrastructure that moves nearly six million riders a day. But lately, it has become plagued by overcrowding, breakdowns and delays. After a series of incidents in the summer of 2017, Governor Andrew Cuomo declared a state of emergency and brought on board Andy Byford, an internationally recognized transit turnaround specialist. How big a problem is Byford facing? What is his plan for getting the subway back on track? Bill Whitaker reports from under the streets of New York for 60 Minutes on Sunday, Oct. 21 at 7:30 p.m. ET and 7 p.m. PT on CBS.

New York's century-old subway relies on antiquated equipment, including a signaling system that dates back to the early 20th century. Whitaker gets a rare, behind the scenes look at the aging equipment in action.