The train ticket beginning with Z is a direct express train.

Direct express trains, referred to as direct special, is a new class of air-conditioned trains for night departure and arrival after the implementation of the fifth major speed increase by the China Railway on April 18, 2004. Before the transfer of the map on December 10, 2014, the direct express trains are mostly one-stop direct, and some of them will stop at the originating station and/or the terminating station within the control of the Road Bureau Group Company Limited, as well as the intermediate stations that have to be technical stops.

After the map adjustment on December 10, 2014, the direct express train was redefined as a "passenger train with a maximum operating speed of 160km/h". The body of the direct express train is unified using 25T type coaches (including 25T type coaches produced by BSP), the maximum permissible operating speed is 160km/h, mainly for the seat for hard sleeper, hard seat and soft sleeper a small number of trains with advanced soft sleeper and soft package.

Direct express train is China's first implementation of a single driver on duty, long-distance trains in the middle of the shift operation, traction locomotives are usually HXD1D-type electric locomotive (Harmony Electric 1D-type electric locomotives), HXD3D-type electric locomotive (Harmony Electric 3D-type electric locomotives), the Dongfeng 11G-type combustion locomotives, Shaoshan 9-type electric locomotives.

Direct express train across the bureau for the number of Z1-Z4998, the number of cars in the tube for the Z5001-Z9998. Railway system standard reading for the "straight ** times", the general public is accustomed to read as "Z ** times". Since November 20, 2011, passengers can order tickets for all direct express trains on the website of China Railway Customer Service Center.

Reference:

Baidu Baike? Direct Express Train