Session: Track 2-1: Rolling Stock and Dynamics

Paper Number: 125901

125901 - Evaluating Draft System Performance 

As part of the Association of American Railroads’ (AAR) Strategic Research Initiatives program, MxV Rail is exploring methods to improve draft system performance evaluations. Draft systems are typically evaluated using drop hammer tests or car-to-car impact tests as specified in the AAR’s Manual of Standards and Recommended Practices (MSRP). These tests provide important information about how draft systems behave and absorb energy in yard-type impact environments, but they do not give enough insight into how draft systems will perform in an in-train environment, where train action performance issues occur. MxV Rail and the End-of-Car Energy Management Task Force of the AAR’s Equipment Engineering Committee are working together to develop a combined testing and modeling approach to evaluate draft system performance. This approach includes both physical impact testing, used to evaluate impact protection and characterize the systems, and modeling, used to evaluate in-train scenarios that are not necessarily covered by existing standards. Train dynamics simulations are a cost-effective and useful addition to the draft system evaluation and qualification process.

Impact tests are useful and necessary tools for evaluating the performance of railcar equipment and freight securement. However, the standards that specify impact test procedures and performance evaluation differ based on the specific application. Impact tests defined in the AAR’s MSRP have a mechanical focus that emphasizes the performance of the railcar and its draft systems. Because of this emphasis, these standards do not necessarily account for freight and securement related effects of the impacts. Similarly, impact tests defined in the Closed Car Loading Standards, such as General Information Bulletin No. 2—Rules and Procedures for Testing of New Loading and Bracing Methods or Materials, have a freight focus that emphasizes the performance of the loading and securement methods but does not account for impact effects on the railcar and the draft systems.

MxV Rail will conduct a series of impact tests using loaded railcars equipped with various draft systems and live loads. The objectives of the impact tests are to 1) evaluate differences between existing mechanical-focused and freight-focused impact tests, 2) characterize the load environment of modern impact scenarios, 3) evaluate the performance of various draft systems during the different impact scenarios, and 4) evaluate the behavior of different commodity types commonly shipped in cushioned cars. The first phase of the impact tests focusses on impacts using loaded boxcars as the hammer car to evaluate a typical closed car loading environment. A future second phase of the impact tests will use loaded bulkhead flatcars to evaluate a typical open top loading environment. These results will be used to help improve the cohesion between existing mechanical- and freight-based impact standards.

Presenting Author: Adam Klopp MxV Rail

Presenting Author Biography: Adam Klopp is a Principal Investigator at MxV Rail. He has 12 years of railroad research and engineering experience. He has extensive experience in vehicle-track interaction and train dynamics. His work has focused on the simulation, analysis, and testing of rail vehicles and trains. He has experience in rail vehicle characterization, rail vehicle modeling, and model validation. His testing experience includes static and dynamic vehicle and track tests, quasi-static end load tests, blast tests, and impact tests. He holds a Bachelor of Science in Mechanical Engineering from Colorado State University-Ft. Collins and a Master of Science in Engineering with emphasis in Railroad Engineering from Colorado State University-Pueblo.

Authors:

Adam Klopp MxV Rail