The Pioneer Zephyr is a diesel-powered trainset built by the Budd Company in 1934 for the Chicago, Burlington and Quincy Railroad (CB&Q), commonly known as the Burlington Route. The trainset was the second internal combustion powered streamliner built for mainline service in the United States, the first such train powered by a diesel engine, and the first to enter revenue service. The trainset consists of one power/RPO car, one baggage/buffet/coach car, and one coach/observation car. The cars are made of stainless steel, permanently articulated together with Jacobs bogies. The construction incorporated recent advances such as shotwelding (a specialized type of spot welding) to join the stainless steel, and unibody construction and articulation to reduce weight. It was the first of nine similarly built trainsets made for Burlington and its technologies were pivotal in the subsequent dieselization of passenger rail service. Its operating economy, speed, and public appeal demonstrated the potential for diesel-electric powered trains to revitalize and restore profitability to passenger rail service that had suffered a catastrophic loss of business with the Great Depression. Originally named the Burlington Zephyr during its demonstration period, it became the "Pioneer Zephyr" as Burlington expanded its fleet of "Zephyr" trainsets.