Chongqing Rail Transit Offers Intense or Mild Cold Carriages Under the Blazing Sun

Chongqing- On August 7, Chongqing Rail Transit (CRT) Loop Line and Line 3 were equipped with intense and mild cold functions to ensure a comfortable journey for citizens in Chongqing.

The meteorological department estimated that the daily maximum temperature of some areas would approach or exceed the maximum historical records of the same period, as intense heat waves linger in many areas of Chongqing.

Chongqing Rail Transit is tagged with Intensive Cold and Mild Cold on the platform door. (iChongqing file photo)

From 26℃ to an optional 25℃ or 27℃

Unlike many places around the world, the set temperature of Chongqing's ordinary trains in summer remains 26℃, an ideal, comfortable room temperature.

For example, the air conditioning of Hong Kong MTR is generally below 26 ℃ according to MTR's Pledge for Services 2022, and some citizens and tourists are likely to bring shawls when traveling, while the seven lines on the UK's Tube network are still without air conditioning in the summer.

The automatic temperature adjusting system of CRT allows the air conditioning system to start its cooling mode when the temperature exceeds 26 ℃. It will turn off the cooling function when it is below 26 °C.

To ensure an even more comfortable transport experience for citizens, Chongqing launched the pilot work of air-conditioning temperature control in the CRT Loop Line and Line 3. The temperatures are adjusted according to the external environment, passenger flow, and feedback.

Intensive Cold (Strong) and Mild Cold (Weak) tags on Chongqing CRT Loop Line and Line 3. (iChongqing/ Zheng Ran)

For example, the platform doors of No. 1-12 and No. 13-24 of the CRT Loop Line are tagged with intense and mild cold, respectively. Depending on their conditions, passengers can choose from carriages with intense cold at 25°C or mild cold at 27°C.

Chongqing will then promote this pilot program on other lines as well. Some program modifications and functional debugging have already started. 

Passengers' temperature perception factors

The temperature can vary slightly between the areas of the CRT's carriage due to the air outlets and air return outlets.

During peak hours, if the air outlet temperature remains unchanged and the number of passengers increases, it will take a little longer for the temperature inside the carriage to reach the target temperature. Some passengers may feel that the temperature is too high.

If there are fewer passengers in the carriage, some passengers, especially the elderly and children who are sensitive to temperature, may feel the temperature is too low.

As the train operates on an elevated line, its interior temperature can also be affected by the intense light and frequent exchange with the outside air.