Two commuter trains crashed during the morning rush hour today in a fiery accident that killed at least 26 people, hospitalized another 150 and raised new safety fears for a nation where millions ride the rails every day.

The collision, about two miles west of London's Paddington Station, ignited diesel fuel tanks on both trains, and the resulting firestorm was so intense that parts of the two trains were fused in a single molten mass. Rescuers spent 13 hours digging through the twisted and smoldering wreckage; they suspended the search for bodies tonight when darkness made the effort dangerous.

Supt. Tony Thompson of the British Transport Police said the search for victims would continue Wednesday morning. All surviving passengers were believed to have been rescued, he said. But as for the dead, "We cannot say how many bodies are left."

The trains crashed on the same stretch of track where another collision two years ago killed seven passengers. A passenger rail company, Great Western Trains, was fined $2.47 million for safety violations in that crash. Great Western operated one of the trains involved in today's disaster.

Deputy Prime Minister John Prescott announced a public inquiry after visiting the scene.

Initial indications suggested that today's smash-up was due to human error--the same error that caused the 1997 crash. That is, "Signal Passed at Danger," the railroad equivalent of running a red light. And in both accidents, an engineer evidently missed the same red light: Signal 109 on the main line linking London to Reading and points west.

Media reports on today's crash said that a two-car local train, operated by Thames Trains, ran through two yellow warning signals and the one red danger light at Signal 109 as it headed westward toward the main line. The local was headed from Paddington to Bedwyn. It evidently curved onto the main line at 8:11 a.m., just as a high-speed Great Western train, heading eastward from Cheltenham to Paddington, reached the crossing. The smaller train reportedly smashed into the Great Western express, knocking the locomotive and the first passenger car off the track and igniting the fuel tanks.

Government and railroad officials would not comment on these reports.

Hundreds of passengers, mainly those in rear cars, got out unscathed or with minor injuries. Those who survived said they could hear the screams of other passengers who were trapped in burning cars and unable to open doors or windows to escape.

Hospital officials said victims had fractures, lacerations and severe burns. Many suffered burns on the lining of their lungs from breathing superheated air.

Since Britain's national railroad was privatized three years ago, passenger service has been divided among 25 companies, while additional companies own the rolling stock and the track. Passenger groups have complained ever since that coordination problems among these competing companies and budgetary concerns have undermined safety.

"There are suggestions that privatization of the railways . . . may have been responsible for these crashes and may have led to a relaxation of safety standards," said Christian Wolmar of Rail Magazine.

Statistically, railroads here have far fewer fatalities per passenger mile than car or bus travel. But cold statistics can't compete with grisly TV pictures of smashed and burning train cars surrounded by bodies of the dead and wounded. Today's crash, accordingly, is likely to revive concerns about the impact of privatization.

Britain's worst previous crash occurred in 1988, when an express train hit a stationary commuter train, killing 35 passengers. A signal fault was blamed for the collision.

CAPTION: Emergency workers investigate the charred remains of a car of one of the two trains that collided during morning rush hour west of London's Paddington Station. The collision ignited diesel fuel tanks on both trains.

CAPTION: An injured passenger is carried from the accident site. Some 150 people were hospitalized with fractures, cuts and burns.