K-series trains

Train numbers are written in the form of K*** or K****, but the letter K reads as "kuai (快)" in station announcements and radio contacts.

[1] The K-series trains first appeared in the first railway speed-up campaign as a service speed level, lower than the T-series but faster than the number-only series.

With more and more short-distance K-series trains are made, the idea of N-series (管内列车) level was brought up in the fifth railway speed-up campaign.

[2] Most K-series trains run using air-conditioned China Railways 25G rolling stock for carriages.

The 22 rolling stocks for K-series are most commonly seen in the northeastern part of China, where some railway lines cannot support 25G carriages to run on.