To the North American railroad industry, FAST® means on-track testing. Since its inception in 1976, the the Facility for Accelerated Service Testing (FAST®) Program has provided a realistic, scientifically controlled environment in which all manner of freight-railway components and systems can be tested—before they are introduced into commercial service. For the past 45+ years FAST® has been a staple of AAR’s Strategic Research Initiatives Program and the proving ground for new technologies tested in a real-world freight railroad setting. At 140 million gross tons per season, this specialized loop is one of a kind in its ability to test components and technologies through fatigue testing in an environment that mimics real-world operations. In 2021, MxV Rail's FAST® Program achieved a significant new milestone in its freight rail research program accumulating 5 billion gross tons of freight train loading. In the rail industry, gross tonnage is the total weight of trains (cars, the loads in them, and the locomotives included) that move through a territory. This landmark accumulation of 5 billion gross tons over a 2.7-mile loop of track is equivalent to taking the current population of the United States (about 331 million people) on a 450-mile train ride. Our work at FAST® is a full-scale research, development, and testing effort aimed at enhancing the safety, reliability, and efficiency of high tonnage, heavy axle load freight rail transportation in North America and around the world. The FAST® program has been very successful in facilitating the safe introduction of new technology into commercial service. We are looking forward not only to continuing, but also expanding this critical and impactful program. The AAR, individual railroads, and railroad suppliers have cooperatively funded and supported operations at FAST® and its many and varied test programs. The cars and the locomotives are loaned to MxV Rail by the AAR member railroads. Rail, ties, bridges, and other components are supplied by industry. The facility offers many advantages for railroad safety and efficiency testing. Operations are closely controlled and varied to suit the needs of each experiment. Comprehensive measurements and observations from the testing support mathematical simulations of track and vehicle systems by supplying the data needed to verify, validate, and calibrate the simulation models.