This is a Federal Railroad Administration notice of availability and request for public comment on Union Pacific Railway's request for amendment (RFA) to its FRA-approved Positive Train Control Implementation Plan. Filed May 22, 2025, the RFA seeks FRA approval to reduce UP's positive train control footprint due to a yard limit extension that does not require PTC implementation. This is not a NEPA document and contains no environmental impact analysis; it is categorically excluded from environmental review.12