The death toll in a train derailment on Monday morning has reached 54 and more than 400 were injured.

　　There are still some passengers trapped in the first carriage that rammed into a nearby apartment building. Four of them have been confirmed alive, according to Japanese media reports.

　　The accident occurred at around 9:20 a.m. (0020 GMT) near a railway crossing in Amagasaki, Hyogo Prefecture.

　　There were several assumptions on what was behind the tragedy. The initial reports said thetrain hit a car and derailed. Other versions included speeding and running over a stone on the track.

　　The seven-carriage train with about 580 passengers aboard tumbled out of the track at a curve. It was one and half minutes behind schedule when setting out from the previous station becauseit overran the platform and had to back up. The 23-year-old train driver, 11 months on the job, overshot a station stop by 100 meters last June, the reports quoted West Japan Railway Co.-- the operator -- as saying. He did not respond to two calls from the control center after leaving the station. Rescuers have yet to locate the whereabouts of the train driver.

　　The company also said there is a high possibility that a stone might have been placed on the track as the sign of crushed stone had been found.

　　Five of the cars derailed with the first two cars badly mangleddue to the smack on the building.

　　The firefighters were providing water to the four survivors in the first car, but one of them showed no reaction, the reports said.

　　The death toll made itself the most serious in Japan since May 14, 1991, when 42 were killed and 527 injured in a collision of two trains in west Japan.

　　The railway company has offered apology, but its president refused to resign. Prime Minister Junichiro Koizumi on Monday night ordered to make all efforts to rescue the trapped survivors and take preciousagainst recurrence of similar accidents.