T = 24: 00-21:00+9: 41=12h41min.
(2) The train travel time from Yanchi to Jingbian is t = 24: 00-22: 39+00: 03 = 84 min =1.4h;
The distance from Yanchi to Jingbian is
s = vt = 100km/h× 1.4h = 140km；
(3) According to the train timetable, the train arrives at the fixed side at 22: 59 and leaves at 23: 05, so the instantaneous speed at 23: 00 is zero.
A:
(1) The one-way running time of Yinchuan-Beijing train is12h41min;
(2) The distance traveled by the train is about140km; ;
(3) The instantaneous speed is 0.