In metropolitan cities, underground railway lines of Mass Rapid Transit Systems are the lifeline to the daily commuters. However, these underground lines cause vibrations while trains move. This ground-borne vibrations may cause damage to heritage buildings and fa & ccedil;ade elements. Humans can feel this vibration, and the comfort of people living nearby is compromised if vibrations cross threshold limit. In the current study, a two-stage coupled analysis is conducted to assess ground-borne vibrations in the free field generated by moving trains in a circular shaped tunnel. Two sub-models are generated-(a) train-track sub-model and (b) tunnel-soil coupling sub-model. The preceding model is a closed-form analytical solution which calculates the quasi-static effect of dynamic interactions between the train wheel and the railway track. The follower model is a 2D FE model to calculate the transfer of dynamic forces from track-tunnel interface to the ground surface through the soil medium. It is found that the computed results fairly match with experimental results for both amplitude and frequency content of the vibration. It is observed that ground vibrations reduce with distance from tunnel and any structure or residents staying beyond 30 m distance would not be affected by vibration as only 25% of vibration is present at this distance. The vibration is found to increase with velocity of train and at soft ground conditions to limit vibration, the velocity of train can be restricted. It is found that the frequency content of vibration is in interference range of human life and critical zone of frequency of structures. Therefore, careful assessment of vibration is required during finalization of the metro project particularly if the ground has shear wave velocity of less than 400 m/s.

The railway transport system is a key factor supporting industrialization in all aspects of human activity. However, in order not to lose its importance, it must meet the challenge of modern civilization. The safety, reliability, and efficiency of railway transport, to a large degree, depend on using highly integrated electronics, which are very sensitive to various disturbances generated in the electric traction system and train or coming from the environment. One of the sources of electromagnetic disturbances are high-voltage (HV) power lines running close to the railway infrastructure. The purpose was to assess the electromagnetic impact of overhead HV transmission lines on buried signaling cables of the railway traffic control system crossbreeding with them. The levels of voltage induced in the cable under steady state and the earth fault in the HV line at various soil resistivity were estimated. A software tool based on a hybrid numerical method that combines circuit theory and electromagnetic field theory was used for computations. It was found that very high voltages may be induced in the signaling cables during earth faults in the HV lines, which may lead to serious interference or damage to the equipment. The results provide useful knowledge for implementing modern railway traffic control systems and protection measures.