Trains can be held up by frozen points,the icing of electice conductor rails,and fog,so warnings are provided by weathermen in time for precautionary measures to be taken.

• 结冰的道岔、用作导电体的铁轨上出现的冰冻、雾等都会使火车停驶，于是气象员及时提供警报以供人们采取预防的措施。