Which Decepticon triple-changer transforms into a train?

Astrotrain is the Decepticon triple-changer that transforms into a train.

Astrotrain has three forms: a robot, a locomotive, and a space shuttle. His train mode is useful for transporting other Decepticons, while his space-shuttle mode gives him an unusual advantage among the faction’s largely Earth-based vehicle characters. The ability to shift between three forms is what makes him a triple-changer.

Astrotrain is most closely associated with the Generation 1 Transformers continuity. In the animated series, he appears as a powerful Decepticon transport and sometimes seeks greater influence within the faction. His alternate modes reflect the franchise’s central idea that one robot can combine alien technology with familiar human vehicles.

The wrong options represent different characters. Springer is an Autobot triple-changer whose forms include a car and helicopter. Blitzwing is a Decepticon triple-changer who becomes a tank and jet fighter. Octane is also a Decepticon triple-changer, but his vehicle modes are a fuel tanker truck and a Boeing 727-style aircraft. Astrotrain is therefore the only listed character whose signature vehicle form is a train.