Exposed to some of the roughest service, gondolas have to be strongly built. In the late 1960s, a 53' gondola with corrugated side panels was introduced by Thrall. The corrugation made the side panels stronger and more resistant to dents and damage. A smooth-side version, designed for service where side-panel strength is not as critical, is also used by numerous railroads.
 
These kits are easy to build, and are offered in a variety of roadnames with corrugated or smooth sides. Undecorated versions of both styles are also available.