The Mail Must Go Through! That famous expression stands for the spirit of the men 邮件必达，这个著名的表达代表着员工的精神，

who have carried the United States Mail. 他们输送美国邮政。

No matter what the danger or hardship, nothing must stop the safe delivery of the messages 不管遇到什么样的艰难险阻，都无法阻止邮件的安全送达，

that the people of our land are sending to each other. 我们土地上的民众相互传递邮件。

From the pony-express riders of long ago to the air-mail pilots of today the same spirit of determination has held true. 从很久以前的骑马传递，到今天的航空邮政，但这份精神依然延续。

This faithfulness to duty has been the spirit of all those whose business it is to see that messages are sent 忠于职守是所有邮递员的精神，他们要确保讯息安全传递，

or that people and things are carried from one place to another. 邮递员和信件从一地到达另一地。

The radio operator must stay at his key on the sinking vessel, flashing out calls for help. 在沉船上，无线电报务员不会擅离职守，而要发出求救信号。

The captain and his crew are the last to leave the ship. 船长和船员是最后离开的人。

The telephone operator stays at the switchboard, warning of the forest fire or the flood that is sweeping down upon the people. 电话报务员会待在总机旁，对侵扰民众的森林大火或洪水发出警告。

The railroad engineer must have a quick mind and a brave heart as he sits at the throttle of his engine. 铁路工程师必须反应敏捷，勇敢果断，因为他在控制引擎。

Men have always wanted to travel speedily and to send messages swiftly from one place to another. 人们总是想快速传递，快速将信息传递给他人。

They have invented powerful machines and delicate instruments to help them do so. 他们发明了强有力的机器和精巧的仪器来帮助实现。

But speed, alone, is not enough. There must be safety. The lives of passengers must be guarded, 但光有速度是不够的，而且要安全，乘客的生命需要得到保证，

and the important message must go through. Always there has been this battle between speed and safety. 重要讯息一定要传达，速度与安全之间总是在矛盾之间。

The machines men make are not human. Skillful hands and courageous hearts must guide them. 人们创造的机器不是人类，精巧的手和勇敢的心必须引导机器。

The stories in this part of your book will tell you about some of the workers 这部分故事将告诉你人们

who send the messages and carry the people of the world swiftly and safely. 又快又安全地将讯息传给全世界。