The noise of narrow-gauge lines is composed of rolling noise and traction motor cooling fan noise. We measured the noise by using a one-dimensional horizontal microphone array and an acoustic mirror microphone. The conclusions obtained for rolling noise from the measured results are that　(a) the spectrum of rolling noise depends on that of rail and wheel roughness; (b) the sound power generated by a wheel with a doubly curved web is greater than that generated by a disc wheel with a singly curved web; and　(c) the noise in the frequency range 1 to 2kHz is mainly due to the wheel vibration generated by the radial directional force at the rail/wheel contact point.

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