In this study, field vibrations were surveyed to investigate travel comfort of two different rail systems in Istanbul and the reasons of low comfort zones. With this purpose, first Aksaray-Airport metro line and then Zeytinburnu-Kabataş tram line were investigated with their superstructure information. For gathering information to determine travel comfort, a 3- axis accelerometer was placed under the seat of driver. And results were determined according to ISO 2631-4 standard. At the end of measurements, total weighted values toward the relevant axis's were obtained with 1/3 octave band acceleration values by applying gains defined in frequency weight filters.