Schemer lives up to his surname by coming up with outlandish and eccentric schemes which always seem to backfire on him. His roguish ways and mannerisms always irritate his very forgiving friends at Shining Time Station. In addition to his interesting wardrobe tastes, Schemer loves to collect nickels, especially from passengers who deposit them into the arcade machines. Other interests include a sizable comb collection. Schemer lives at home with his mother, and is known to have at least one sibling who lives out of town who is the parent of his nephew Schemee.
Horace Schemer is the spitting image of his grandfather, Jebediah Schemer, and is fiercely proud of one prominant trait of the Schemer bloodline, the telltale curl on the side of his head. A follower of his own "Schemer's System of Success", which often if not always lands him into trouble, Schemer does occasionally reveal a caring side of personality to his friends. Schemer's clumsiness sometimes sends him tumbling to land flat on his face, though he manages to do so without any serious injury to himself. Schemer steadfastly believes Shining Time Station to be haunted, although his fears are largely due to the occasional unseen antics of Mr. Conductor and The Jukebox Band members.
- Season 1 - A Place Unlike Any Other (credit only), Does It Bite?, And the Band Played Off, Pitching In and Helping Out, Show and Yell, Faith, Hope and Anxiety, Agree to Disagree, Whistle While You Work, Two Old Hands, Happy Accidents, Ring in the Old, Impractical Jokes, Finders Keepers, Just Wild About Harry's Workshop, Promises, Promises, Word's Out, Too Many Cooks, Mapping it Out, Things that Go Ga-Hooga in the Night, Is This the End? and 'Tis A Gift
- Season 2 - Scare Dares, Oh, What a Tangled Web, The Magic is Believing, Win, Lose or Draw, Sweet and Sour, Achoo, A Dog's Life, Field Day, Wrong Track, Washout, Crackpot, Yabba, Yabba, Yabba, Nickel in a Pickle, Stop the Press, He Loves Me, He Loves Me Not, Double Trouble, Is Anybody There?, Do I Hear, Jingle, Jingle, Jingle and All's Fair
- Season 3 - Becky Makes a Wish, Schemer's Alone, Bully for Mr. Conductor, Stacy Cleans Up, Schemer's Robot, Billy Saves the Day, Billy's Party, Fortune Teller Schemer, Billy's Runaway Train, Schemer Goes Camping, Mr. Conductor's Evil Twin, Bad Luck Day at Shining Time Station, Mr. Conductor's Fourth of July, Stacy Forgets Her Name, Schemer's Special Club, Mr. Conductor's Movie, The Joke's on Schemer, Dance Crazy, Mysterious Stranger, Dan's Big Race, Mr. Conductor Gets Left Out, Mr. Conductor's Big Sleepwalk, The Mayor Runs for Re-Election, Stacy Says No and How the Station Got Its Name (mentioned)
- The Family Specials - Once Upon a Time, Second Chances, One of the Family and Queen for a Day
- Schemer Presents! - How to Get Something Done, How to Have Style à la Schemer, How to Use a Telephone, How to Share, How to be Smart, How to Tie your Shoes, How to Clean Up Your Room, How to Have Good Table Manners, The Meaning of Time and How to Apologize
- Mr. Conductor's Thomas Tales - Wish You Were Here (mentioned)
- "Schemer's system of success: ..."
- Schemer, whenever he tries to impress someone
- "This place is haunted!"
- "You call this place Shining Time Station? Hmph! There nothing shining about it! Yuck!"
- Schemer, Whistle While You Work
- (has a meltdown) "My mommy's gone! My mommy's gone and I don't even know how to brush my teeth by myself! I mean look at all this stuff she wants me to do: "take out the trash", "make your bed", "say please and thank you". I mean what does she think I am? Some kind of mature adult?"
- Schemer, Schemer's Alone
- Schemer must have a brother or sister in order to have a nephew, Schemee.
- In the Shining Time Station home video collections, Schemer was given his own spin-off at the end of each volume. Some of these shorts were later given their own release.
- Brian O'Connor, as Schemer, sent an email to Sodor Island Forums more than 10 years after the series ended.
- Schemer's collection of checkered sport-jackets is in large part thanks to actor Brian O'Connor making use of his father's own clothes.
- The idea of Schemer's curl and obsession with nickels and money was thanks to Brian O'Connor, adding ideas that would suit the character.
- Schemer is considered to be a comic relief character.