This is why trains have round-shaped lids on outer roof 

All of us must have enjoyed train journey. But most of us are ignorant about various signs, numbers, and letters printed on trains. Basic knowledge about such things can certainly make our journey safe as well as enjoyable. 

Have you ever noticed round-shaped covers fitted on the roof of the train? Have you ever wondered what they are for? 

Let’s understand the reason behind this. 

These round-shaped lids can’t be seen from inside the coaches. That can be noticed from outside, from bridges or railway over bridges or railway foot over bridges when a train passes under them. 

These lids are not for mere design. They play a vital role in making the passengers’ journey enjoyable. 

These lids are called ‘roof ventilators’. From the name, you can guess their role. Yes, they are to ventilate the humidity generated inside a coach. 

At times, the number of passengers in coaches increases. This generates excess heat and causes suffocation. In such conditions, it would be difficult for the passengers to enjoy their journey. 

In order to exude this heat and suffocation, trains are specially designed in such a manner. They have ‘roof ventilators’ on their rooftops as hot air always goes up. 

While travelling, you must have noticed plates with holes fitted onto the roof from the inside. Through these inner holes, the hot air finds an outlet and goes out through the roof ventilators on the top of the roof. 

The round-shaped lids are so designed and placed as to prevent rainwater from entering the coach.