United Aircraft Corporation TurboTrain

Either way, these trains were fast. On December 20, 1967 a TurboTrain reached 170.8 mph during acceptance testing on a high-speed test track on Penn Central’s mainline. UAC’s creation not only beat the competing Metroliner project, but blasted past the speeds of what the Shinkansen could do back then.

The TurboTrain was put into service in both the United States and Canada in 1968.

[due to being plagued by many obstacles, mishaps, and setbacks] Today, you won’t find a UAC TurboTrain anywhere. Just seven trainsets were built and all met the scrapper. They now only exist in riders’ memories, the internet, and scale models.

https://www.theautopian.com/the-uac-turbotrain-was-americas-failed-plane-engined-high-speed-train-of-the-future/