In 1936–39 Palestinian Arabs opposed to Jewish mass immigration revolted against British rule. Railways were a particular target for sabotage. The British built blockhouses to protect bridges and regular military patrols of railway lines. Patrols were initially on foot, then in armoured freight vans propelled by locomotives with armoured cabs, and finally with dozens of rail-mounted armoured cars built at Qishon works. After one was blown up by a mine, killing a soldier, the front of each armoured car was fitted with a long bar propelling a pony truck intended to detonate any mine safely without injuring any of the armoured car's occupants. British soldiers made Arab hostages ride on the pony truck so that any mine would be likely to kill them.