The merger of Union Pacific Railroad with Missouri Pacific and Western Pacific took effect on January 1st, 1983. In March 1983, Western Pacific GP40 3532 was painted in UP yellow and gray while retaining WP lettering. While a large number of MP diesels would be painted in UP colors with MP lettering, WP 3532 would be the only WP engine so decorated – the rest of the WP diesels that would be retained were renumbered and repainted by December 1983. On August 9th, 1983, unique WP 3532 was assigned to the local that switched the Hunt-Wesson plant in Fullerton, California. Passing through Fullerton's Sunny Hills, the line crossed a (cement-lined) creek, at which point the trackage descended downgrade into the plant and a crossing of the Santa Fe ("Basta" on the ATSF), before heading east parallel to the Santa Fe through Fullerton and south to Anaheim. Thirteen years earlier, on February 18th, 1970, the UP local left they caboose partly on the crossing at Basta and it was struck by an eastbound Santa Fe freight – You can see a photo from Joe McMillan of the aftermath of this tragic accident HERE.
