The down train is odd (odd). For example, T 1 1 time is from Beijing to Shenyang in the north, so it is odd (odd) because it is descending; Its return train T 12 is from Shenyang north to Beijing, which is upward, so it is even (even).
Extended data:
Train classification and trips, trains are divided into four categories.
1, new speed passenger train: EMU with a speed of more than 200 kilometers per hour is used to run on the line with a speed of more than 200 kilometers per hour.
2. Express passenger train: The train with the speed of 140-160km per hour will be used, and it will run on the line with the speed of140km or more.
3. Express passenger train: use the bottom of the train with a speed of more than120km, and stop at a larger station.
4. Ordinary passenger trains: including ordinary passenger express trains and ordinary passenger slow trains, with the train bed at a speed of100-120km per hour, and stop at the station according to the passenger demand. Ordinary passengers stop at the local train without being limited by the stopping distance.
Baidu Encyclopedia-China Railway Train Rules