Question: The character Keiko Toda voiced in "Thomas & Friends" is based on what book series?
Context: Tara Chambler is a fictional character from the horror drama television series "The Walking Dead", which airs on AMC in the United States and is based on the comic book series of the same name"."  The character is based on Tara Chalmers from "", a novel based on the comic book series and the past of the Governor.  She is portrayed by Alanna Masterson.  She is the first character identified as LGBT to be introduced in the series. Rosalind Chia-Ling Chao ( ; ; born  () ) is an American actress.  Chao's best-known roles have been as a star of CBS's "AfterMASH" portraying South Korean refugee Soon-Lee Klinger for both seasons, and the recurring character Keiko O'Brien with twenty-seven appearances on the syndicated science fiction series "" and "". Natasha "Tasha" Yar is a fictional character that mainly appeared in the of the American science fiction television series "".  Portrayed by Denise Crosby, she is chief of security aboard the Starfleet starship USS "Enterprise"-D and carries the rank of lieutenant.  The character's concept was originally based upon the character of Vasquez from the 1986 film "Aliens".  Following further development she became known first as Tanya, and then Tasha.  Crosby had originally auditioned for the role of Deanna Troi, while Rosalind Chao became a favorite for Tasha.  After Marina Sirtis auditioned for the role, the show's creator Gene Roddenberry decided to switch the roles for the actresses, with Sirtis becoming Troi and Crosby becoming Yar.  Chao would later appear on the series in a recurring role as Keiko O'Brien. Apache Chief is a Native American superhero from the various "Super Friends" cartoons, which were created by Hanna-Barbera and the DC comic book series of the same name.  He was one of the new heroes added (along with Black Vulcan, Rima the Jungle Girl, El Dorado and Samurai) to increase the number of non-white characters in the Super Friends ranks.  He was voiced by Michael Rye in most of his appearances, Regis Cordic in his debut appearance and Al Fann in "History of Doom". "New Game! " is an anime television series based on the manga series created by Shōtarō Tokunō and published in Houbunsha's "Manga Time Kirara Carat" magazine.  The series follows Aoba Suzukaze, a high school graduate who begins working at the Eagle Jump video game company as a character designer.  The anime is produced by Doga Kobo, with Yoshiyuki Fujiwara as the director and Fumihiko Shimo as the series' script supervisor, featuring character designs by Ai Kikuchi.  The first season aired in Japan between July 4 and September 19, 2016 and was simulcast by Crunchyroll.  An original video animation (OVA) episode was available for those who purchased all six Blu-Ray/DVD volumes of the series, released between September 28, 2016 and February 24, 2017.  The opening and ending themes respectively are "Sakura Skip" (SAKURAスキップ , Sakura Sukippu ) and "Now Loading!!!" , both performed by Fourfolium (Yūki Takada, Megumi Yamaguchi, Ayumi Takeo, and Megumi Toda).  A second season titled "New Game!!"  aired between July 11 and September 26, 2017.  The second season's opening theme is "Step by Step Up ↑↑↑↑" while the ending themes are "Jumpin' Jump Up!!!!"  for the first six episodes and "Yumeiro Compass" (ユメイロコンパス , Dream-colored Compass ) for episode seven onwards, all performed by Fourfolium.  The series is licensed in North America by Funimation, who are releasing English dubs of both seasons. "Stop!!  Hibari-kun! " is a 35-episode Japanese anime television series based on the manga series of the same name written and illustrated by Hisashi Eguchi.  It is directed by Takashi Hisaoka and produced by the animation studio Toei Animation.  The screenplay was written by: Shigeru Yanagawa, Tokio Tsuchiya, Hiroshi Toda, Tomomi Tsutsui, Takeshi Shudo and Yumi Asano.  The character design used in the anime was provided by Yoshinori Kanemori, and the music was composed by Kōji Nishimura.  The series follows Kōsaku Sakamoto, a high school student who goes to live with yakuza boss Ibari Ōzora and his four children—Tsugumi, Tsubame, Hibari and Suzume—after the death of his mother.  Kōsaku is shocked to learn that Hibari, who looks and behaves as a girl, was assigned male at birth. Thomas the Tank Engine is a fictional steam locomotive in "The Railway Series" books by the Reverend Wilbert Awdry and his son, Christopher.  He became the most popular character in the series, and is the title character in the accompanying television spin-off series, "Thomas & Friends". Shūichi Ikeda (池田 秀一 , Ikeda Shūichi , born on December 2, 1949 in Tokyo) is a Japanese actor and voice actor.  Ikeda is married to Sakiko Tamagawa, although he was once married to Keiko Toda.  He currently works for Tokyo Actor's Consumer's Cooperative Society.  He is best known for his role as Char Aznable in multiple Gundam series Shuichi Akai from Detective Conan and Red Haired Shanks from One Piece. Keiko Toda (戸田 恵子 , Toda Keiko , born September 12, 1957 in Nagoya, Aichi) is a Japanese actress and voice actress.  Her most famous role is the voice of the children's hero Anpanman on the long running anime "Soreike!  Anpanman".  She was also the voice of Thomas the Tank Engine in the Japanese dub of "Thomas & Friends" from Season 1 to Season 8.  She was once married to Shuichi Ikeda. Eric Northman is a fictional character in "The Southern Vampire Mysteries," a series of thirteen books written by "New York Times" bestselling author Charlaine Harris.  He is a vampire, slightly over one thousand years old, and is first introduced in the first novel, "Dead Until Dark" and appears in all subsequent novels.  Since the book series is told from the first person perspective of Sookie Stackhouse, what readers perceive of his character is influenced by what Sookie comprehends.  HBO's television series "True Blood" is based on this book series and the character of Eric Northman is portrayed somewhat differently.  A list of "True Blood" characters has a detailed description of Eric's character from the TV show.
Answer: "The Railway Series"