A cost-effective method of experimentally determining rail vehicle dynamic parameters for use in analytical dynamic models has been developed by the Association of American Railroads (AAR). In this method, the rail vehicle’s rigid body modes of vibration are manually excited and the corresponding resonant frequencies are measured. Using these frequencies, the equations of motion for the system are solved for the vehicle’s mass moments of inertias, center of gravity location, and suspension stiffness. This method of dynamic parameter identification was developed at AAR’s Transportation Technology Center, Pueblo, Colorado. Compared to competing experimental methods, the AAR method offers the advantage of cost-effectiveness; it requires no expensive equipment and can be executed at remote locations. This paper describes the AAR method for rail vehicle parameter identification. An example of its use in the characterization of an iron ore rail vehicle is presented. In addition, dynamic simulation results for a transit vehicle, characterized using the AAR method, are compared to track test data for validation.

Currently, the U.S. Navy's preferred fuel of all fossil-fueled, surface ship power systems is a middle distillate fuel conforming to the requirements of MIL-F-16884H, Fuel, Naval Distillate (NATO F-76). In recent years, the Navy has been finding it more difficult to obtain F-76, especially in foreign ports. In order to address the potential problem of reduced F-76 availability and to begin planning for the introduction of synthetic fuels such as shale oil products, the Energy Research and Development Office of the David W. Taylor Naval Ship Research and Development Center commissioned a shipboard fuels flexibility study. The overall objective of this program is to develop a comprehensive strategy for using a broadened specification fuel on board Navy ships. This paper presents a summary of work performed to characterize commercial marine fuels from various countries around the globe. Since the marine fuels marketplace is the most likely source of alternate fuels to be used by the Navy, characterization of the fuels in this marketplace is a necessary step in the development of a broadened fuel specification. Fuels of primary (near term) interest are marine gas oils and heavy marine gas oils; those of secondary interest are marine diesel fuels and intermediate fuel oils.

Currently, the U.S. Navy's preferred fuel for all fossil-fueled, surface ship power systems is a middle distillate fuel conforming to the requirements of MIL-F-16884H, Fuel, Naval Distillate (NATO F-76). In recent years, Navy ships have been finding it increasingly difficult to obtain F-76, especially in foreign ports, and this tightly specified fuel is generally more expensive than its civilian counterparts. To address the potential problem of reduced availability and to begin planning for the introduction of synthetic fuels such as shale oil products, the Energy Research and Development Office of the David W. Taylor Naval Ship Research and Development Center commissioned a shipboard fuels flexibility study. The overall objective of this program was to develop a comprehensive strategy for using a broadened specification fuel on board Navy ships. As part of the shipboard fuels flexibility program, shipboard fuel testing procedures were evaluated that could be used by Navy personnel on board ship to judge the acceptability of fuels not procured under MIL-F-16884H. As such, the study was divided into three subtasks: 1. Evaluation of shipboard fuel testing procedures currently used on board Navy and commercial marine vessels. 2. Determination of fuel testing procedures required for shipboard screening of non-specification fuels and the adequacy of available procedures. 3. Recommendation of a test protocol and the development or refinement of additional shipboard fuel testing procedures. This paper summarizes the results of those subtasks. Test protocols, which could be used for shipboard testing of nonspecification fuels obtained outside the Navy's fuel logistics system, are presented for: 1. Marine gas oil (MGO)—a middistillate fuel containing no residual fuel oil, the marine equivalent to Nos. 1-D and 2-D fuels. 2. Marine diesel fuel (MDF)—a middistillate fuel heavier than a marine gas oil, containing less than 10% residual fuel oil, frequently as a result of contamination. 3. Intermediate fuel oil (IFO)—a blend of heavy residual fuel oil and marine gas oil or marine diesel fuel. The proposed procedures and instruments for each protocol are discussed as well as the sequence in which they would be performed. Manpower requirements, as well as the cost and space associated with each protocol, are reviewed. Areas where additional research or development are required are identified with recommendations for such activities.