A runaway boxcar is about to run over five people walking on the tracks. A railroad worker is standing next to a switch that can turn the boxcar onto a side track, killing one person, but allowing the five to survive.
1. 一个失控的货车车厢就要撞到正在轨道上行走的五个人了。一个铁路工人站在道岔转换旁边。那个道岔转换可以把车厢转到岔道上，撞死一个人，但是可以让五个人活下来。扳道岔是______。