The Federal Railroad Administration intends to award a sole-source purchase order to Jensen Hughes, Inc. to continue developing a physics-based model that quantifies fire and toxic hazards of lithium-ion batteries in rail applications. This follow-on effort will use module-level test data to calibrate and validate the computer model established under a prior competitive contract. The work aims to establish a systematic methodology for determining the Heat Release Rate of complex battery energy storage systems to inform safety mitigation measures. Responses from interested parties demonstrating capability to perform this effort must be received by July 18, 2026, at 12:00 PM EST. No budget amount or performance location is specified in the description.