Chongqing is about to break its own record for the deepest subway station in China.

The southwestern city, located in an area crisscrossed by rivers and mountains, is building train platforms 94.46 meters underground as part of the ongoing extension of the Chongqing Metro network.

Hongtudi station, which opened on Line 6 in December 2014, was already the country's deepest station at 60 meters below ground. Now, it is being pushed even deeper to connect with Line 10, which is under construction.

The extension, which is scheduled to open by the end of the year, will have high-speed elevators that drop 78.8 meters - about 26 stories - another national record, according to the city's transportation authorities.

Ninety-one escalators, China's largest escalator network, will be installed to move passengers between lines 6 and 10 and the surface.

To enter or leave Hongtudi station now, people need to take escalators with a 30-degree incline on a journey lasting three minutes and 15 seconds. The alternative is a stairwell with 354 steps.

Chen Limei, 30, a tourist from Hunan province, said she finds the station "magical".

"It's the first time I've taken such a long escalator, and it seems never-ending, one after another," she said. "It would be very interesting if we could take a slide from the top."

Some passengers complained that it wastes time to take such a long journey.

"These escalators are too long and slow, and the trip takes too much time," said a man surnamed Liu, 24.

The expansion of Hongtudi station will make it one of the deepest in the world. The world's deepest subway system is said to be the Pyongyang Metro in Democratic People's Republic of Korea, which has tracks more than 110 meters underground.

Arsenalna station on the Kiev Metro's Sviatoshynsko-Brovarska Line in Ukraine is 105.5 meters below the surface. Commuters have to take two escalators to the bottom, which takes up to five minutes.

The Admiralteyskaya station in Russia's St. Petersburg Metro system is 86 meters below ground.

Chongqing also boasts the highest overpass in the country, at 72 meters. From windows on the 22nd floor of a nearby building, people can look across at the overpass and see the traffic.

tanyingzi@chinadaily.com.cn