Stochastic Technical Stability Test of a Passenger Railroad Car Crossing a Turnout

This article presents a definition of stochastic technical stability that was applied to test a mathematical model of a passenger railroad car crossing a turnout with the speed exceeding 160 km/h. Stability defined in this way allows testing of Lyapunov’s stability with disturbances from the track and for a nonlinear system. The STS test of a nonlinear mathematical model of a passenger car was carried out by perturbing the motion of the mathematical model with irregularities originating from the track gauge change and wheelset motion in the direction transverse to the track axis. The main aim of this paper was to determine the influence of various factors and technical conditions on the assessment of the stability of various means of transport. The analysis presented can be used to assess the dynamics of electric vehicles, whose mechanical parameters differ from those of combustion vehicles at present. The area of stable motion in the Lyapunov sense was defined using the STS method. Simulations were performed to determine the trajectory of the wheelset transverse motion. The probability of finding the wheelset in the stable motion area in relation to the rail for a single-point contact was determined. In practice, this is a one-point contact of the wheel with the rail. Conclusions from the conducted research are presented.

Understanding Why Railroad Yard Crews Run Through Misaligned Switches Through the Lens of Sociotechnical Systems

We conducted a study to examine the factors that contribute to run through switches (RTS) in passenger rail yard operations. RTS occur when a train runs through a misaligned switch. It can result in damage to the switch that, if not detected and repaired, can increase the risk of derailment of a subsequent train coming in the opposite direction. The study was conducted at one passenger railroad and included interviews and focus groups with employees at different levels in the organization, as well as observations of yard operations. A sociotechnical systems perspective was used to identify physical infrastructure, individual, team and organizational contributors to RTS. This included performing a Systems Theoretic Process Analysis (STPA) to identify how interacting factors can lead to RTS. This paper provides a summary of the main results. It illustrates the value of adopting a sociotechnical lens when investigating safety incidents that involve human performance.

Passenger Railroad Facility Safety Audit as Revenue Protection

Thousands of slip, trip, missteps and fall accidents and train collisions occur each year at railroad stations, terminals, and grade crossings resulting in serious injuries causing a significant drain of financial resources. This paper provides guidance in identifying common safety hazards and easy ways to reduce or eliminate these dangers. This paper will cover a variety of safety issues, which are commonly present in a railroad environment. It also provides estimates regarding the cost of railroad related pedestrian accidents. More than 95 percent of injuries on rail system injuries are minor. The top one percent of injury claims can account for 20 percent of the total claims’ cost.

Evaluation of Occupant Volume Strength in Conventional Passenger Railroad Equipment

To ensure a level of occupant volume protection, passenger railway equipment operating on mainline railroads in the United States must be designed to resist an 800,000-lb compressive load applied statically along the line of draft. An alternative manner of evaluating the strength of the occupied volume is sought, which will ensure the same level of protection for occupants of the equipment as the current test, but will allow for a greater variety of equipment to be evaluated. A finite element (FE) model of the structural components of a railcar has been applied to examine the existing compressive strength test and evaluate selected alternate testing scenarios. Using simplified geometric and material properties, a generic single-level railcar model was constructed that captured the gross behaviors of the railcar without excessive processing time. When loaded, the carbody structure exhibits some single beam-like behaviors. Application of the existing 800 kip compressive load results in a significant bending moment as well as significant compressive forces. The alternative load cases examined show that a larger total compressive force may be distributed across the end structure of the railcar and result in similar stress levels throughout the structural frame as observed from application of the conventional proof load.

Measurement and Analysis of Acela Express Regenerative Power Recovery

Amtrak launched the first high-speed Acela Express passenger train service in the USA in 2000 on the Northeast Corridor (NEC) between Washington, D.C, New York, and Boston. The NEC infrastructure is used by several other railroad/transit agencies that operate commuter train services under operating access agreements with Amtrak. With such an arrangement, all NEC passenger railroad/transit agencies contribute to the electrical demands of the traction power system on the southern division and in particular, between New York, and Washington, D.C. Amtrak and the other railroad/transit agencies conduct periodic reviews of the cost-sharing arrangements for the electricity bills. As part of a recent review, accurate data on the power usage by the Acela Express fleet was needed. The Acela Express power cars are equipped with modern traction drives with controls that are capable of recovering some or all of the regenerative braking power they produce. The use of regenerative braking is automatically controlled by the onboard Braking Control Computer via the internal propulsion and braking network. This feature makes the Acela Express trains efficient in energy consumption and affects the cost allocation to Amtrak. The extent of the energy recovery is dependent on how receptive the traction power system is when power is being regenerated from braking. In order to obtain realistic data, two separate Acela Express power cars were instrumented. A large amount of data was collected in normal service conditions from the onboard instrumentation. This paper describes the instrumentation and the data collection procedure, and presents the analysis results of the collected data. The analyses were focused on two parameters: the “energy recovery ratio” and the “system receptivity” of the traction power supply system. The study contributed to the successful conclusion of a new electrical cost-sharing arrangement among the NEC passenger railroad/transit agencies, which was made public in October 2006.