Rescuers are struggling on Wednesday to reach seven workers who have been trapped in a flooded railway tunnel in central China's Hubei Province since early Sunday morning.

"But the chances of survival for them are slim," a rescuer told Xinhua.

The fatal flooding occurred at around 1:00 AM on Sunday in the Yesanguan rail tunnel in Enshi Tujia and Miao Autonomous Prefecture, trapping 52 workers, and 43 workers were rescued later the same day.

Three workers were confirmed to have died, following the death of one of the rescued workers on Monday after emergency treatment failed and the retrieve of two bodies late Monday night from the tunnel.

The workers were possibly buried by mud and rocks at two sites underground, said Tan Zhengbiao, general manager of China Railway 16th Group Co., Ltd, the tunnel builders.

Rescuers are still searching the tunnels, repairing shafts that have caved in, pumping out water and clearing up the silt underground. The runoff inside the tunnel was three cubic meters per second on Tuesday afternoon.

The 14-km tunnel is the longest of the 121 tunnels along the Yiwan Railway, which links Yichang City in Hubei Province with Wanzhou in Chongqing Municipality.

Rescuers said the accident happened at a site 240 meters from the tunnel mouth.

Silt has clogged an area 150 meters from the entrance to the tunnel and, in some areas, the mud and rock reach four meters high, the local rescue headquarters said.

Heavy rains have triggered severe flooding and mudslides in many parts of central China in the past few weeks.

(Xinhua News Agency August 8, 2007)