It's an important job hauling ballast - that's the material needed to fix the lines on the Island of Sodor. As part of the Sodor Railway Repair team, little engineers make the ride safe and smooth for Thomas & Friends.
This unusual-looking machine appears in one illustration in Small Railway Engines. It is a complicated machine used for replacing old ballast on the Fat Controller's Railway. In the illustration it is painted bright yellow and carries the words "SODOR CHAIN LOAD UNDERCUT" on its side. Unusually, it appears to be wearing glasses.
The name "Sodor Railway Repair Train" is technically inaccurate as it belongs to the North Western Railway! This machine is also called a ballast spreader.
Repair car have swivelling ballast loader arms.
The Sodor Railway Repair Cars is a retired set. It was retired in 2002. As such, stocks are limited and may be difficult to replace. It is however currently available from Thomas to You.