SL-Man is a sentient steam locomotive character in the Anpanman universe, functioning primarily as rail transportation for goods and passengers, including children. His debut occurs in Episode 62a, where he is discovered rusted and non-functional after a storm causes a tree to fall on him. The antagonist Baikinman recovers him, mistakenly assuming SL-Man lacks sentience. Revived by consuming fruit from Dokeen, SL-Man feels indebted to Baikinman and Dokeen, leading him to be deceived into viewing hero Anpanman as an enemy. This manipulation culminates in SL-Man attempting to push Anpanman's bakery off a cliff. Anpanman intervenes, revealing Baikinman's deception and convincing SL-Man to abandon the villains.

SL-Man possesses locomotive-specific abilities: emitting an "SOS" distress signal through his smokestack and generating defensive black smoke to obstruct adversaries like Baikinman. His design draws inspiration from Thomas the Tank Engine, with "SL" on his cab abbreviating "steam locomotive." Real-world steam locomotive limitations apply to him, including dependency on a coal tender and inability to travel underwater.

His relationships are sparse, with Poppo-chan explicitly identified as his sole child through narrative interactions, notably featured in Episode 1089a. SL-Man's popularity in Japan, driven by cultural appreciation for steam trains, secured his frequent reappearances after his debut.

Beyond the anime, SL-Man features in dedicated media like the DVD collection *Soreike! Anpanman Daisuki Character Series / SL Man "Baikinman to SL Man"*, compiling five episodes centered on him. Another DVD, *Soreike! Anpanman Daisuki Character Series Poppo Chan SL Man to Poppo Ch*, highlights his bond with Poppo-chan. Physical representations include a life-sized ride at Kobe's Anpanman Children's Museum, a scaled-down ride for younger children at the Osaka museum, and playground equipment at the Takashi Yanase Memorial Hall.