Modernize your HO Scale intermodal fleet in minutes with WaltherMainline Thrall Rebuilt 40' Well Cars! As the 53' container quickly became the standard for domestic shipping, older well cars built to carry 48' boxes soon fell out of favor with railroads. Most were only a few years old, so starting in 2003 Thrall began a rebuilding program that shortened the wells to the standard 40'. Today they can be seen carrying 20' and 40' containers in the well, with 40' and 53' units on top. Fully assembled and ready for service.