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The vibration of the rails is a significant source of railway rolling noise, often forming the dominant component of noise in the important frequency region between 400 and 2000 Hz. The purpose of the paper is to investigate the influence of the ground profile and the presence of the train body on the sound radiation from the rail.

Two-dimensional boundary element calculations are used, in which the rail vibration is the source. The ground profile and various different shapes of train body are introduced in the model, and results are observed in terms of sound power and sound pressure. Comparisons are also made with vibro-acoustic measurements performed with and without a train present.

The sound radiated by the rail in the absence of the train body is strongly attenuated by shielding due to the ballast shoulder. When the train body is present, the sound from the vertical rail motion is reflected back down toward the track where it is partly absorbed by the ballast. Nevertheless, the sound pressure at the trackside is increased by typically 0–5 dB. For the lateral vibration of the rail, the effects are much smaller. Once the sound power is known, the sound pressure with the train present can be approximated reasonably well with simple line source directivities.

Numerical models used to predict the sound radiation from railway rails have generally neglected the influence of the ground profile and reflections from the underside of the train body on the sound power and directivity of the rail. These effects are studied in a systematic way including comparisons with measurements.

The public’s awareness of noise and vibration forms a significant barrier to further development of railways. This chapter begins with a short introduction to the main fundamental aspects of acoustics, including decibels, frequency analysis, the propagation of sound with distance and common measurement quantities. The main sources of railway noise are discussed, including rolling noise, impact noise, curve squeal and aerodynamic noise. Simple calculation procedures are described that can be used to assess the impact of railway noise and to compare it with legal limits. The final section is devoted to ground vibration, which is a related form of environmental disturbance.

The vehicle–track interaction and the resulting dynamic response of the vehicle involve a number of complex nonlinear problems. Large vertical loads act through a small contact patch leading to very high contact pressures. Transverse loads acting through this contact induce a relative velocity between wheel and rail expressed in non-dimensional form as a creepage. The wheel and rail profiles determine the contact patch shape and affect the ability of the vehicle to run stably. If the yaw stiffness of the axles is too low, the vehicle will become unstable at a relatively low speed; conversely, if the yaw stiffness is too high, the curving behaviour will be adversely affected. The vehicle suspension, especially the secondary suspension, also affects the ride comfort of passengers. Finally, it is shown how the speed profiles of accelerating and decelerating trains can be calculated from basic assumptions about the train power, adhesion and rolling resistance.

This book has reviewed the sustainability of rail engineering and operations with respect to both existing assets and new build in terms of the three pillars of economic, social and environmental sustainability. It is argued that the composition of a sustainable railway is well understood, but there are practical issues with delivery. These issues may be overcome with an emphasis on infrastructure provision, finance (and funding), top-down governance and bottom-up participation.