The contours will not change. Steep inclines must be taken slowly, changes of direction taken with great care. The tracks were laid long ago, but nothing is automatic. Sometimes they become very complex as you meet others on the track, sometimes travelling the same direction, sometimes opposite, sometimes crossing yours. At the points you can easily skip the tracks or find yourself jolted and jolting too harshly.
People make mistakes.
Take it easy in such yards. Look for the signals. Stop, if need be and wait. Your challenge is not to keep time but to keep those entrusted to you. That may sometimes include detours and delays.