Standardization of High-Wide Load Measurement Using Laser-Based Technology

Each year, thousands of open-top loads are shipped across North America over the Class I railroad network. Many of these loads are high-value, high-risk shipments, presenting considerable operational challenges for the carriers due to special handling requirements. Shipments that extend beyond a standard geometric envelope, denoted by various “plates” in the Association of American Railroads (AAR) Open Top Loading Rules (OTLR), are considered to be over dimensional, or High-Wide Loads (HWLs). Historically, railroad mechanical personnel have measured HWLs manually using a tape measure, plumb line, level, and various homemade devices. Measurement methodologies and philosophies can vary widely among mechanical inspectors. As a result, railroads have recently sought out new technologies to standardize the measurement process, resulting in greater safety, efficiency, accuracy and documentation. Taking the lead in this effort, Norfolk Southern Corp. (NS), BNSF Railway and Union Pacific Railroad have all worked closely with InfraMeasure, Inc. in their development of a patent pending, portable, laser-based measurement system known as SafeLoad®. This paper documents the development of this technology, including the completion of successful repeatability tests and the training of dozens of car inspectors from multiple railroads on the use of the system. In 2014, laser-based measurement technology was deployed across the entire NS network and was also used extensively by Union Pacific Railroad. In addition, BNSF and other Class I railroads began testing with the thought of implementing in the near future. Repeatability tests performed among newly trained employees indicated high levels of precision, with field measurements deviating by no more than 0.25 inches among various inspectors. Additional field testing confirmed a reduction in labor time and personnel required to measure HWLs by as much as one half while significantly improving measurement accuracy and reducing fall related risks by eliminating the need to climb on HWLs. In addition to these immediate benefits, the early stages of implementation have highlighted a potential long-term need for standardized measurement training within the industry. Anticipating the growing knowledge gap left by attrition, railroad mechanical departments are placing greater emphasis on training new car inspectors to assume the safety critical task of HWL measurement. This paper explores the current state of HWL measurement in the US railroad industry and identifies potential solutions, using technology, to further standardize both the practice of measuring HWLs and the training of new inspectors.