Canadian police on Monday struggled to find the remains of people killed when a driverless crude oil train derailed and blew up in a small Quebec town over the weekend as questions grew over how the disaster had occurred. The five locomotives and 72 oil cars had been parked about eight miles from Lac-Megantic on Friday night. The brakes then somehow released and the train gathered pace as it rolled down a hill into the center of the town early on Saturday morning. It derailed and exploded into a gigantic fireball, flattening dozens of buildings and killing five people. Another 40 are missing and few residents hold out hope that they will be found alive.