Blaine the Mono

Blaine the Mono was a major antagonist in Stephen King's The Dark Tower Series. He was a pink train (mono-rail). Blaine made appearances in The Waste Lands and Wizard and Glass. He was alone so long that it drove him mad, and he even killed his counterpart, Patricia the Mono, because she complained to much. He was planning on killing himself before reaching Topeka, and then decided to bring Roland and his ka-tet with him.

Before The Dark Tower Series
Blaine was a monorail developed by the Old Ones, with dipolar computers housed under Lud. His original purpose was to house passengers to Topeka, making stops in Candleton, Rilea, The Falls of the Hounds, and Dasherville.

His top speed was 900 miles an hour. Even though he existed in Mid-World he still knew information on the Americas.

He assisted in Patricia's death by removing part of her programming. During his slope into insanity, Blaine developed a rogue part of his brain that was dubbed "Little Blaine". Little Blaine was fearful of the much more dominate "Big Blaine" and wanted to stop him, but couldn't.

The Waste Lands
Eddie and Susannah found Blaine resting in The Cradle of Lud. When Roland, Jake and Oy reunited with Eddie and Susannah, Blaine had already started releasing nerve gas in Lud. Before the group could board Blaine, they had to solve a riddle, which Susannah did before the gas reached them. While on Blaine, he informed them that he was planning suicide, and he was going to drop of the rails at Topeka, with the ka-tet on him.

Roland asked Blaine to spare them, if they could give Blaine a riddle that he couldn't solve.

Wizard and Glass
Blaine answers every riddle the group can give him, without pausing. He knows the answer to every riddle. It is only through Eddie's goofy riddles, that Roland deemed "unworthy", that the group was saved. Blaine grew furious, as the answers to Eddie's riddles were so bizarre, and in the end his brain was fried. His body continued to move towards Topeka. He crashes there, but luckily his speed decreased enough that the ka-tet could jump off in time.