This is a Federal Railroad Administration notice of availability and request for public comment on Alaska Railroad's (ARR) request for amendment (RFA) to its FRA-approved Positive Train Control Safety Plan (PTCSP). Filed July 18, 2024, the RFA seeks FRA approval of a material modification to ARR's Interoperable Electronic Train Management System (I-ETMS): an onboard software upgrade intended to improve operational efficiency during high-volume passenger traffic in Alaska's tourist season. This is a procedural regulatory notice, not a NEPA environmental review; no alternatives or environmental impacts are analyzed.12