Field trials of the fifth-generation (5G) mobile communication system using 28GHz band at which almost 1GHz bandwidth will be available have been performed all over the world. To realize large coverage with such a high frequency band, beamforming by Massive MIMO (Multiple Input Multiple Output) is necessary to compensate the large path loss. Furthermore, beam tracking which adaptively changes beam direction according to user location, is an important function to support user mobility. In previous works, field trials in subway environment at 25GHz band was carried out, but only fixed beam were employed. On the other hand, the field trials result of 28 GHz-band 5G transmission employing beam tracking in the road environment has been reported. Therefore, we conducted 5G field trials in the actual railway environment using 28GHz band experimental equipment employing beam tracking. This paper reveals the downlink performance achieved by using railway cars traveling at 90km/h. In addition, we show how mobile stations position in the railway car affects the performance of 5G transmission.