The Short Line Safety Institute (SLSI) measures short line and regional railroads’ safety culture using a multi-method assessment process that examines safety culture performance across the U.S. Department of Transportation (DOT) Safety Council’s 10 Core Elements of a Strong Safety Culture (Morrow & Coplen, 2017). This document summarizes findings from an analysis of safety culture growth across 20 short line railroads that completed both an initial (Time 1) and follow-up (Time 2) Safety Culture Assessment (SCA) by SLSI. In this analysis, the Volpe National Transportation Systems Center (Volpe) staff established Time 1 and Time 2 safety culture scores for each railroad, using outputs from SLSI’s SCA process. Volpe staff then measured railroads’ safety culture growth within the 10 Core Elements. While the analysis revealed safety culture growth across all railroads and within all 10 Core Elements, the magnitude of improvement varied by railroad and Core Element.