AlHijjah 2, 1432, Oct 29, 2011, SPA -- A truck that flipped over Saturday in Northwest China, killing 23 people, was not designed to carry passengers, UPI cited officials as saying. The crash occurred at about 7:30 a.m. local time in a railway tunnel under construction in Gansu province, Xinhua, the official government news agency, reported. The truck was being used to ferry construction workers to their job site on the railway, although it was authorized to carry no more than two people in the cab with the back used for cargo. The driver and 20 of the workers were pronounced dead at the scene. Two died after emergency surgery, and the remaining five were in serious condition, a spokesman for Dingxi Municipal People's Hospital said. The tunnel is in a mountainous area near Dingxi. The railway line is to connect the city of Lanzhou in northwestern China with Chongquing in the southwest. A traffic police spokesman said a brake failure appears to have been the reason for the crash, which is still under investigation.