This Marlines set is one of several variations that I know of. There are differing letter styles and boldy moldings used for the boxcar, gondola, caboose, and tender. There are also obvious differences in the colors used for the gondolas and boxcars.
There is another set from the same era which pulled six inch tin cars. The tender, lettered MARLINES, has smaller lettering.
These little sets from the early to mid 1950's are hard to find!