Hi, the subway between these two station has not been opened until now. One possible method for you: take the subway Line 2 at Beijing Railway Station and then transfer to Line 1 at Fuxingmen Station, finally get off at Military Museum Station. Out of the subway station, you could find the city-buses of 320, 21, 40 and 414 taking you to Beijing West Railway Station quickly, just two stops~ or, you could ride a taxi, just cost 10RMB