Introduced in Lionel's 1981 catalog is the GP-35 diesel. One of the hallmarks of this era of Lionel production was innovating with existing toolings. The 1981 GP-35 is a prime example. The body is basically the GP-9 with an angled Spartan-cab roofline labeled as a GP-35. The rear radiator fans are modified from the usual appearance on the GP-9 shell. The model returns in Lionel's 1982 catalog, but is listed as a GP-9. Maybe even Lionel wasn't sold on the idea that this beast was a GP-35?