A fast development of high speed railways is witnessed in recent years as well as the performance of its wireless communication systems, GSM-R. In GSM-R systems, a large percentage of call outage is induced by handoff process. Thus, handover is a critical issue of reliability performance in GSM-R systems. Most of existing investigation and practical designs for handover in GSM-R systems are mainly based on single antenna without considering the specificity of the train as hard handover. In this paper, we take full use of the length of the train and propose a novel scheme of seamless fast handover based on Dual-Antenna. In this scheme, two antennas are respectively installed at the head and the end of the train and the proper coordination of the two antennas turn it to a soft handover. In the interlacing area of two antenna cells, the head antenna handover in advance while the end antenna connects to the current cell until the front antenna connect the new cell reliably. In this way, we can achieve a seamless and fast soft handover. This paper introduces the details of the scheme and analyzes the feasibility. Simulation results show that the proposed scheme is more efficient than existing schemes in terms of handover delay and reliability.