Railway steel plate girder (SPG) bridges generally are provided with open track which does not have ballast cushion. Tracks consisting of steel channel sleepers with under sleeper pads are being used in Indian Railways. In the present work the combined track-girder system is modelled as two beams connected with uniformly distributed springs and dampers. A computer program in MATLAB has been developed to examine the effect of track on the behaviour of girder. A train of ten wagons travelling on a ten-span bridge is studied. Shifts in the fundamental frequencies of the girder due to inclusion of track in modelling are analyzed. The significant findings are that: (i) the natural frequencies of combined track-girder system differ from those of the girder alone and (ii) in the case of multiple simply supported spans, the presence of the track in dynamic modelling influences the dynamic behaviour of neighbouring spans. Finally, the dynamic behaviour of the girder is studied using moving force model (MFM) for different velocities and a comparison is made for two cases, viz. (i) girder alone modelled neglecting the track stiffness and damping, but considering the track mass; and (ii) girder and track modelled as two beams connected through uniformly distributed springs and dampers, i.e., both the track stiffness and mass are considered. For case (ii), mid-span acceleration varies from 20% to 80% and impact factor for displacement varies from 26% to 96%, of those of case (i). The results confirm that the presence of track in dynamic modelling influences the dynamic behaviour of the open deck SPG.