The Fandom Post is reporting that the Steamboy anime film has been added to Amazon Prime. The film is available in its English dubbed form with closed-captioned English subtitles available for it.
Steamboy is described as:
A retro science-fiction epic set in Victorian England, Steamboy features an inventor prodigy named Ray Steam, who receives a mysterious metal ball containing a new form of energy capable of powering an entire nation, the Steam Ball. Young Ray Steam must use the Steam Ball to fight evil, redeem his family, and save London from destruction.
Source: The Fandom Post