Muni has apparently started attaching straps across the gaps between train cars to prevent people from trying to climb over the couplings.
SFMTA spokesperson Paul Rose said the agency is testing the straps for 30 days before installing them on the entire articulated train fleet. They’re intended to help “prevent, deter or warn patrons from inadvertently stepping off an elevated platform to the trackway below in between two light rail vehicle cars,” he said. The bright-green straps are retractable, so they maintain a straight line as the trains turn.
Attempting to cross the gap is extremely dangerous, and it does happen: In February, a woman was injured while trying to squeeze  between an N-Judah train with her dog on Irving Street at 2nd Avenue. She was trapped underneath and dragged for half a block, and escaped with only scrapes and bruises (the dog was unharmed). An SFPD spokesperson told CBS  that she was “very, very lucky” to not get caught under the wheels.