Crash investigators in England have begun looking for the causes of a train crash that killed at least 27 people and injured 160 near a London rail station yesterday.

The trains collided at 8:11 a.m., three kilometres west of London's Paddington Station.

A British Broadcasting Corporation reporter says the initial investigation suggests one of the trains passed one red and two yellow warning signals before hitting the other train.

Meanwhile, the search for more victims resumed at dawn today . Rescue workers picked through the wreckage, trying to account for missing passengers.

Of the 150 people taken to area hospitals, reports say at least 14 are seriously injured.

Many passengers cried as they described how they frantically crawled out broken windows in the aftermath. Others said they were haunted by the cries of those trapped in the wreckage.

Authorities could not determine the total number of passengers aboard the trains.

Great Western and Thames Trains are the companies that operate the two trains involved in the crash.

Great Western said as many as 500 people might have been on board its train, which originated in Cheltenham, northwest of London, and was minutes away from its destination of Paddington Station. The Thames train, which may have been carrying up to 150 passengers, had just pulled out of the London station.

Reports said both trains were traveling about 100 km\/h when the Thames train tried to cross in front of the Great Western train.

Rail travel is a way of daily life for many people in London and its surrounding communities. About 800,000 people travel into and around London by train everyday.

Tuesday's accident was Britain's worst rail crash since December 1988, when three trains collided outside London's Clapham Junction, killing 35 people.

1. What did the search for more victims resume at dawn?