On June 8, 2000, at 1025 hours Pacific daylight time, a Mooney M20D, N31M, made a forced landing in a railroad yard and collided with a sand dune southwest of Baker, California. The airplane sustained substantial damage; however, the certificated private pilot received no injury. The pilot was operating the airplane as a personal cross-country flight under the provisions of 14 CFR Part 91. The flight departed from Walker Field in Grand Junction, Colorado, en route to the Big Bear Airport, California, earlier that day. Day visual meteorological conditions prevailed at the time, and a flight plan had not been filed. The pilot reported that he had noticed a fuel pressure fluctuation, which began while he was just north of the Grand Canyon. He switched fuel tanks from right to left after his observation and the pressure returned to normal (about 4 pounds per square inch). Another fluctuation was noticed upon switching back to the right tank 1 hour later. The pilot activated the electric fuel pump and it remedied the situation. He left the electric fuel pump running as the leg continued for another hour. The tanks were switched again, at which time the electric pump was turned off. The fuel pressure started to fluctuate and dropped to zero after a 25-minute period had passed. It was at this point that the engine completely stopped running. The pilot attempted to bring the engine back on-line by maneuvering the airplane and using various engine out procedures. Cycling the fuel selector, electric pump switch, adjusting the mixture, and carburetor heat did not have any effect. The airplane received radar flight following service from Los Angeles Center. Radar contact was lost at 1023. According to the pilot, he declared an emergency and made a forced landing on a rail service road about 20 miles southwest of Baker. During the landing sequence, the airplane received a 3-foot tear to the left wing's leading edge, and the right main landing gear had collapsed. A San Bernardino County sheriff's deputy responded to the scene and found very minimal fuel in the right fuel tank of the airplane. The deputy also reported that when the electrical master switch had been placed in the on position, the quantity gauges did indicate fuel on board. The next day, retrieval personnel recovered less that 1 quart of fuel from the fuel tanks. On June 14, 2000, a Safety Board investigator successfully ran the engine at Aircraft Recovery Services, Compton, California. At the time of the test and examination, the investigator noted that the engine fuel pressure was 4.5 pounds per square inch (psi) with the electric fuel boost pump in the on position. The pressure was 3.5 psi with engine boost pump in the off position. The engine idled and accelerated smoothly. The owner conducted a post crash inspection of the airplane and discovered contamination in the fuel selector assembly. He took photos of the fuel selector body and strainer. The particles in the body were orange in color, and they had accumulated under the fuel selector screen. The owner told the Safety Board investigator that he had resealed the tanks with a compound similar in color to the debris found in the fuel screen area. Review of the aircraft maintenance records indicated that both fuel bays were repaired in December 1997. An annual inspection was performed in December 1999. The mechanic who performed the annual inspection and repairs did not recall finding any unusual contamination at the time. A tachometer time of 3,523 hours had been recorded in the aircraft log for this inspection. The Mooney service manual recommends that fuel screens should be checked for contamination every 50-flight hours, and about 43 hours had accrued since the last inspection.