| Portland Terminal S3 1101, South Portland, Maine May 9, 1984, photo by Chuck Zeiler. This was the only S-3 on PT's roster. In 1949 the AAR adopted the General Steel Castings (GSC) rigid bolster truck as a Recommended Practice (RP). Alco made some modest upgrades to the S-1, replacing the Blunt truck with the AAR RP truck, designating the upgrade as E1530A, or S-3. In addition to the truck change, more use was made of welded assembly, and rubber gaskets were used for the windows. This locomotive was powered by a six cylinder 660 horsepower McIntosh & Seymour Model 539 normally aspired diesel engine. |