Technical Reports

A Comparative Risk Assessment of Remote Control Locomotive Operations versus Conventional Yard Switching Operations

  • 01
  • May
  • 2006
AUTHOR: Stephen Reinach, Steven Fadden1, Frederick Gamst2, Sarah Acton, and Simon Bartlett1
KEYWORDS: Remote control locomotive operations, portable locomotive control, railroad safety, remote
ABSTRACT: This report presents a comparative risk assessment of U.S. remote control locomotive (RCL) and conventional yard switching operations. First, a hierarchical task analysis (HTA) was conducted to provide a detailed description of yard switching tasks. Based on the HTA results, a preliminary hazard analysis (PHA) and human reliability assessment (HRA) were performed. For each method of switching operation, the PHA identified a worst credible scenario for 19 potential outcomes. Each scenario was assigned a risk score based on an assessment of the likelihood of occurrence and potential severity. The HRA consisted of two complementary techniques: the Human Error Assessment and Reduction Technique (HEART) and Absolute Probability Judgment (APJ). A set of yard operating scenarios was developed to provide the basis for the HEART and APJ assessments. Analysis of PHA variables indicated that the 19 RCL worst credible scenarios yielded higher risk scores compared to similar conventional worst credible scenarios. The HEART assessment did not reveal any differences between the two methods of operation in terms of human error probabilities (HEP). Substantial variability existed in HEP assignments between HEART assessors, suggesting that HEART may be inappropriate as an HRA technique for the railroad yard switching environment. Fourteen railroad operating employees participated in four APJ assessments. While individual HEP values varied across a large range, the patterns in the data show a trend toward greater HEP for RCL scenarios. The HEART and APJ data, however, should be considered preliminary and interpreted with caution, due to the study’s subjective nature, numerous study limitations, and methodological challenges. These limitations and challenges are discussed.