The MBTA is still slowing things down

In March, the entire 'T' system reduced its speed to a max of 25 miles per hour after a Red Line inspection revealed defects the MBTA could not account for. The systemwide slowdown was lifted in a day but around a fifth of the tracks are still on speed restriction. Boston Globe video producer Olivia Yarvis set out to find out how slow these "slow zones" are and what's being done to fix them.