Katy Caboose is Tootle's own caboose.
Tootle's trusty caboose, who accompanies Tootle on both passenger and goods trains. Katy is much more responsible with work than Tootle, and often acts as his guide around the railways. Katy cares greatly for Tootle and doesn't like staying away from him for long, but she is willing to call him out when he does things wrong. Katy acts as a big sister to Tootle, guiding the young engine she always travels with through tough times and mistakes he must overcome. She's patient and very tolerant around everyone, even the toughest engine. Overall, she's kind, gentle, and the perfect companion for young Tootle.
- Katy Caboose and Tootle originated from the book 'Tootle' from the Little Golden Book' series.