कोशी की जीवन रेखा — मानसी सहरसा रेलखंड - Prabhat Sharan

In this video, at the end as the train begins to accelerate, one can hear a chugging like sound which comes from underneath the coaches in a rhythmic fashion. I've experienced this 3-4 times in different coaches. What sound is that can you elaborate?

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The sound is of "Flat Tyre" often caused by Break Binding or sudden jamming of wheel due to breaks.
Up to 5 mm is acceptable.

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I liked the video-definitely not boring:)

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