The Kantan Sisters (カンタンシスターズ) are characters in the Anpanman anime.
They are twin sisters who work on machinery including vehicles. The one with the red hat and the plus sign is Pla-chan (プラちゃん) and the one with the blue hat with the minus sign is Mai-chan (マイちゃん).
The twins makes their first appearance in an episode featuring Shokupanman (September 17, 1990). (Translate episode name please?)