The high noise levels of the New York City MTA subway system—often exceeding 75 to 100 decibels—are caused by several structural and mechanical factors. Primarily, the system's steel-on-steel friction between the train wheels and the tracks, especially on sharp curves, creates a high-pitched "screeching" sound. Many of the tunnels are nearly a century old and made of hard concrete and steel, which reflect and amplify sound rather than absorbing it. In 2026, the MTA has also faced criticism for the addition of 75-decibel digital advertisements on platforms, adding to the ambient roar. While newer train models have improved suspension and insulation, the sheer age of the infrastructure and the lack of modern noise-dampening ballast in many underground sections mean that commuters are often exposed to noise levels that exceed safety thresholds recommended by the WHO.