The 6,384-hour ATP rated pilot, with 69-hours in make/model, lost directional control of the tailwheel-equipped single-engine airplane during the takeoff roll from a 3,740 foot long by 60 foot wide asphalt runway. The pilot reported that the airplane's controls responded correctly as he taxied his homebuilt airplane from his hangar to runway 14 prior to his departure. Prior to taking the active runway, the pilot reported that he executed a 360-degree clockwise turn to visually check for approaching aircraft followed by a left turn onto the active runway. During the takeoff roll, the airplane began to swerve to the left side of the runway. The pilot further reported that he attempted to arrest the swerve by applying right rudder; however, the airplane did not respond. The airplane exited the left side of the runway and impacted a berm and a nearby railroad track. An FAA inspector reported that an examination of the airplane's flight controls and tailwheel assembly did not reveal any pre-accident anomalies. The pilot was attempting to depart from Runway 14. The weather observation facility located 6 nautical miles northeast from the accident site reported the winds from 220 degrees at 6 knots.