Ryu is a mixed-traffic engine who works on the Upper Valley Railway.
Ryu was originally built to run the Mainland's line between Keikan and Tanishima, along with Hiro and No. 12. After the line was closed in 1955, he was purchased and brought to the Upper Valley Railway. He has since continued with mixed traffic, though primarily maintains passenger duties with Morning Light. He will pull the Sunlight Express if there's no other engine available.
During the New Year's Blizzard of 1954, he was one of the engines to go up the Ice Line on the rescue mission. Later, he and No. 12 stayed at the Valley Station for the New Year's celebration, against their Controller's orders.
Ryu began his life obnoxious and lazy; under the shadow of the famous Master of the Railway, Ryu developed a bad attitude towards the Tanishima engines. Hiro taught him as best he could, but it wasn't until he left that his lessons began to sink in to Ryu. After his repaint, he decided that he likes to work now (though mainly because he likes to show off), and is much friendlier to other engines. He looks after No. 12, and is good friends with Misaki and Morning Light.
Ryu is painted UVR Green with yellow stripes, with "UVR" on his tender and his number on the side of his cab. His name is written in black on gold nameplates, on each side of his smokebox. He was originally painted black with gold bands and fittings and red wheels, with his old number "50" painted on the sides of his tender in white.
Ryu is based on the C50 class JNR Class 50 redesigned for standard gauge.
Ryu appears in the following books:
- Volume 04: Katsu the Mine Engine (introduced)
- Volume 06: Hiro the Wise Engine
- Volume 08: Naomi the Steam Coach Engine (mentioned)
- Volume 09: Misaki the Big Tank Engine
- Volume 11: Hideaki the New Engine
He also appears in Smudger and Hiro's Winter Adventure, and will be appearing in Battle for the Mountain.