This railway is built of very high soil. A big ditch divides the railway into two long parallel lines, then scatters thick pebbles and lays heavy rails on them. The rails were cut into pieces, and the railway workers tied them together to prevent damage and replacement. I asked my father, "Why do you put stones under the tracks?" Dad told me: "Without paving stones, the rails are not stable enough, and the train will vibrate violently when passing by." The train is very heavy, which will cause the rails to sink and the train will naturally fail to start. " When it rains, stones can also filter rainwater, without loosening the soil below and without weeds. "Dad just finished, my mother added," It's convenient and economical to sprinkle gravel, and it also has the function of silencing. "Finally, my parents asked me to measure them. Ah, these pebbles are 20 centimeters thick.
Then the station dispatcher came out with a small red flag. Is the train coming? Sure enough, a few minutes later, a long truck sped from a distance with a flute, and then gradually slowed down as it approached the platform, twisting like a bug and making a deafening crash. Dad added: "When the train arrives or leaves the station, it will whistle for a long time;" In case of danger, long whistle and three short rings; Whistle two long sounds when retreating; If it makes a rapid and continuous short sound, tell another train that there is danger in front of the adjacent line and stop quickly. " Ah, the train also has vivid language!
I learned a lot today. What about you?