Combustion engine tends to create more vibration, which translated to more sound. this will cause the wheel to vibrate with the track, which will cause more noise from wheel hitting the track by vibration of the engine. The electric trains don't have this issue.

In 2026, electric trains are significantly quieter than their diesel counterparts, primarily because they lack the loud internal combustion engines that characterize traditional locomotives. When an electric train pulls into a station, the "roar" and "idle" noise of a diesel engine are replaced by a soft electrical hum and the sound of cooling fans. Research in 2025 and 2026 highlights that the majority of noise from high-speed electric trains actually comes from aerodynamic drag and the physical friction of wheels on steel rails (rolling noise), rather than the propulsion system itself. At lower speeds, such as during station arrivals or urban transit, electric trains are nearly silent, which has led to improved air quality and reduced noise pollution in metropolitan areas. However, this "silence" has necessitated the use of more frequent horn blasts or automated warning sounds at level crossings to ensure the safety of pedestrians who may not hear the train approaching.