Why does the train go “to-duh, to-duh” when it rides?

The “to-duh, to-duh” sound that a train makes when it rides is caused by a phenomenon known as “rail corrugation.” This occurs when the train’s wheels roll over the metal rails, which are typically made of steel. The steel rails have a series of ridges and grooves, which the wheels roll over. As the wheels roll over the ridges, they vibrate, causing a sound that is similar to “to-duh, to-duh.” This sound is amplified as the train moves faster, and can be heard from a great distance.

Rail corrugation can be a major problem for trains, as it can cause excessive wear and tear on the wheels and rails. To reduce the effects of rail corrugation, railway companies use a variety of methods, such as installing smoother rails, using special lubricants, and regularly inspecting and replacing worn out rails.