Two train tunnels from the station head west out of the basement, beneath the Hudson, where they join other tunnels.During building, the walls of the basement were secured against the pressure of surrounding soil and water by anchoring them to the bedrock with steel cables. When completed, the basement floors braced against the walls took the strain, and the cables were cut.With the basement floors now destroyed or damaged, engineers believe only debris is preventing the walls from collapsing in on themselves. If that happened it would let mud and water pour in.The engineers plan to get into the tunnels – not expected to be possible for weeks – and block the tunnels with huge concrete plugs.. One floor beneath the World Trade Centre, in what used to be a shopping concourse, a clock on a jewellery store wall remained frozen at 9.10 and a ghostly Bugs Bunny statue stood coated in grey dust outside a Warner Brothers gift shop near by.As the stores in the underground mall were checked one by one for survivors, rescue workers marked them with an orange X.

They made one stroke of the X as they went in, the other as they came out. Wearing what looked like miners' helmets, search crews from the Federal Emergency Management Agency (FEMA) picked through the rubble and the darkness under 5 World Trade Centre on Tuesday, burrowing into any space big enough to shield a survivor. The nine-storey section of the Trade Centre was charred but did not collapse when the complex's 110-storey twin towers crumbled on September 11."There are caverns down here," said Don Schroeder, commander of a FEMA unit from Sacramento, California. "The focus is to continue to find and extract victims from a pile of rubble like this."He said he had no doubt a person could have survived in the spaces the workers found, but nobody has been found alive so far. He said some bodies were recovered when crews tunnelled into the concourse but could not say how many.The mall was dark except for headlamp beams and some daylight that fell through the shaft of a stalled escalator Broken glass crunched underfoot The air was stale and stifling Workers wore heavy, elaborate filter masks.

Canisters of oxygen were on hand if needed.At the Tourneau jewellery shop, where eight clocks displayed time from around the world, local time had stopped at 9.10 – about 25 minutes after terrorists began their attack.The workers from the Urban Rescue team based in Sacramento, California, were among eight 62-member teams on duty from California, Ohio, Indiana, Missouri, Florida and Pennsylvania.They searched by hand through the corridors of the concourse, pulling aside rubble, peering into spaces and snaking in a fibre optic camera when they could burrow no farther. Harley, a golden retriever, helped sniff for victims.Outside, the daunting rescue and recovery efforts continued in orderly fashion Cranes lifted large pieces of rubble from a great crater. A big rubbish bin was set aside, labelled "AIRPLANE PARTS".Flyers were posted throughout the area, showing workers a picture of an aeroplane's black box. The flight recorders of the two airliners that brought down the twin towers have not been found.Signs in the windows above said "God Bless America", "R.I.P." and "Kill Them All – Let Allah Sort Them Out."Above the entrance to 5 World Trade Centre, below which the FEMA team was working, was a sign that read: "Open Every Day" (AP). It was more than a week since the twin towers crashed to the ground in downtown Manhattan crushing thousands of people, but the elation for this young police officer was instant There in the rubble, he saw a foot and a spine.