MULTAN, Pakistan—Two express trains collided in southern Pakistan early Monday, killing more than 30 passengers, authorities said, as rescuers and villagers worked to pull injured people and more bodies from the wreckage. Between 15 to 20 passengers are still trapped in the wreckage of the Millat Express train and authorities were trying to arrange heavy machinery to rescue those people who are crying for help, said Umar Tufail, a police chief in Ghotki district in Sindh province, where the collision occurred before dawn. The Millat Express derailed and the Sir Syed Express train hit it soon afterward, said Usman Abdullah, a deputy commissioner in Ghotki. It wasn’t immediately clear what caused the derailment and the subsequent collision. “Right now the challenge for us is to quickly rescue those passengers who are still trapped in the wreckage,” he said. Abdullah said so far 30 people had died. According to railway officials, …