Metro power shift on the night shift

An overhead line modification at Chenxiang Road Station on Metro Line 11 took over 300 workers a mere three hours.

Chenxiang Road Station on Metro Line 11, a new elevated station between Malu and Nanxiang stations, will open in the first half of 2020, said Shanghai Metro.

An overhead line modification on Tuesday took over 300 workers only three hours to connect cables over 1,600 meters of track.

The system which powers the trains has two carrier cables and two overhead lines.

“It is almost impossible to add a new underground station to a Metro line without interrupting the operation of the line,” said Qin Kangqian, manager of the Chenxiang Road project. “It is doable for an elevated Metro line, though there are a lot of difficulties.”

One major problem is the timescale. Workers had to finish more than 10 operations to connect the lines after the line closed on Monday and before the first passenger train departed from Huaqiao Station at 5:40am on Tuesday.

Work began at 0:30am. If 1,600 meters sounds long enough, the workers actually had to replace over 3,000 meters of cable. More than 2,900 meters were installed over the weekend, with similar time limits.

Qin said the overhaul was not because of the cables themselves, but the pillars they hang would have obstructed the screen doors on the new platform.

“We divided the system into different sections so that even if one section is out, the others still work,” said Qin. “Pillars linking overhead line sections can’t be installed in a Metro station.”

The workers moved the pillars 270 meters south last week.

Apart from having little time, the curve of tracks and limitation on machines were also huge challenges.

Chen Qingsong from China Tiesiju Civil Engineering Group, the contractor, said since the work had to be done late at night, the huge diesel rail trolley used to carry materials had to be muted. According to regulations, every time the engine starts, a whistle should sound for 10 seconds. Instead, the workers kept reminding each other so the horn on the trolley remained silent.

“The college entrance examination is coming up, so we have to ensure a quiet night for students,” said Chen.

Around three quarters of the tracks under the overhead lines were curved, which put high demands on the team.

“We have more than 300 workers high above the ground,” said Chen. “We must be very careful.”

Chenxiang Road Station was first planned to serve a proposed amusement park in the area, but as the park project stalled, so did the station.

Recently, residential complexes were built in the area and a major shopping mall, InCity, is under construction. The distance between Nanxiang and Malu stations is 6 kilometers, quite an inconvenience for people living in between. In January 2018, construction of the new station started.

Line 11 is the longest Metro line in Shanghai, covering 82.4 kilometers from Huaqiao Station in Kunshan, Jiangsu Province, to the Disney Resort. About 900,000 people use Line 11 every day, making it the sixth of the 17 Metro lines in passenger flow.

Metro power shift on the night shift
Deng Jiahao / Ti Gong

Overhead lines are modified at Chenxiang Road Station on Tuesday. 

Metro power shift on the night shift
Deng Jiahao / Ti Gong

Workers toil through the night to get the work done.

Metro power shift on the night shift
Deng Jiahao / Ti Gong

The huge track trolley is muted during the construction to allow students studying for gaokao, or college entrance examination, to get a good night's sleep.

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