Recently, noise and vibration problems are gaining increasing importance in railway vehicles for passengers. They chose railway vehicles as a purpose of transport and also for carrying out sedentary activities like reading, writing, etc. There are, however, several important factors inside the vehicle environment that hinder such activities. One of the main sources of disturbance for the passengers is internal vibration generated from the vehicle itself. The internal vibration levels in railway vehicles have been decreased step by step during recent years due to the fact that stiff requirements on passenger activities and comfort. This paper presents the results of the measurements and analysis of the vibrations to which passengers and crew are exposed in Istanbul metro. According to the measurement and analysis results, the superstructure fixed on concrete with applied rehabilitation project zones are determined much more comfortable than the old superstructure. These measurements demonstrate the role of rail maintenance in minimizing the vibration levels in the metro.