The direction of railway entering Beijing or from branch line to trunk line is called ascending, and the direction of leaving Beijing or from trunk line to branch line is called descending. The number of trains going up is even (even) and the number of trains going down is odd (odd). K 1337 is odd, because it is from Jinan to Urumqi. Its return train k 1336 is from Shenyang north to Beijing, which is upward, so it is even (even).

Extended data:

K 1336 and k 1337 pass the following stations: Jinan, Yancheng, Yucheng, Pingyuan, Dezhou, Hengshui, Xinji, Jinzhou, Shijiazhuang North, Yangquan North, Taiyuan, Jiaocheng, Fenyang, Lvliang, Jingbian, Dingbian, Zhongwei, Wuwei, Jinchang.

Baidu Encyclopedia-China Railway Train Rules