European authorities hope to be able to increase the volume of freight and passengers that are transported on railway systems compared to those transported on roads. If that policy is successful the problem of noise from railway traffic will increase. It is know from previous research that measures against the noise are more efficient if applied directly at the source itself rather than using indirect measures such as noise barriers and increased window insulation. This report is a literature survey on how the railway noise is generated, and to what extend different measures at the source can reduce the noise emission. The report also briefly describes what limits and recommendations on noise exposure are enforced now and in the near future. Furthermore the noise propagation methods used for calculating the noise level at different receiver positions (noise exposure) from the noise emission are discussed.