Pioneer Zephyr was a three-car articulated diesel-electric trainset built by the Budd Company for the Chicago, Burlington & Quincy Railroad in 1934.
It carried the road number 9900 and was originally simply called the Zephyr before later trainsets made the Pioneer name necessary.
The train used stainless-steel construction, allowing a light but strong body that resisted corrosion.
Its Winton diesel engine drove a generator that supplied electricity to traction motors, combining internal-combustion power with electric transmission.
On May 26, 1934 the train made its famous “Dawn-to-Dusk” run from Denver to Chicago.
The roughly 1,000-mile trip was completed in about 13 hours, creating enormous publicity for streamlined diesel rail travel.
The run was a demonstration and publicity event, not a normal everyday schedule at that exact speed.
Pioneer Zephyr subsequently entered revenue service and worked in several assignments over its career.
Unlike Union Pacific M-10000, the original Pioneer Zephyr survives and is preserved at the Museum of Science and Industry in Chicago.
For TransitSatellite, the page should distinguish the preserved original trainset from later Burlington Zephyrs that used the same branding but different equipment.