The factory installed various safety measures such as emergency stop buttons and guard rails.

safety 是名词，意思是"安全"，指避免危险或伤害的状态。 measures 是名词 measure 的复数形式，measure 本义是"测量、措施"，在这里指"预防措施"或"防护手段"。 safety measures 指"安全措施"或"安全防护装置"，是为预防事故或伤害而采取的各种预防性措施和设备。