China: Shanghai Sinking- Water leakage in Shanghai train stations.

SHANGHAI: Heavy rain over the past week in Shanghai has put the spotlight on the safety of metro train operations, after water leaked into stations on almost all metro lines.

One of the stations affected by water leakages was metro line 10.

There were leakages in the station and the train platform.

Channel NewsAsia understands in some cases, there were also water leakages inside the trains.

Plastic bags and pails had been used to collect the water, and the operator has placed anti-slip rugs and sandbags in the station to keep the water out.

Five million passengers use the Shanghai metro daily, which is one of the fastest growing rapid transit systems in the world.

The operator said the building projects are awarded to different contractors and some may lack experience in the construction process, resulting in the water leakages.

Another cause of the water leakages, especially at recently built stations, is subsidence, which will take several years to settle.

Subsidence, or land sinking at uneven rates, causes cracks which result in leakages.

Experts said a large number of construction projects in one area will speed up subsidence.

For example, the construction near the metro station may cause further sinking if not monitored properly.

In Shanghai, the problem of subsidence is worsened by rapid urbanisation.

It is believed that in some areas, land is sinking on a average of two to four centimetres a year.

The city has sunk about two metres in the last century.

Apart from subsidence, other issues have also been raised in the wake of the water leakages.

For instance, the entrance to the metro line 10 underground station is without shelter, which allows rain water to flow into the station directly.

The train operator also said because many of the stations are built on land lower than the drainage pipe network, water has to flow upwards through a pump, slowing down the drainage process.

The train operator is looking at how to prevent this from happening in new stations being built now.
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