Chicago Line Toy Company Flatcar, with Tractor and Trailer. Model No. 1617.
My thanks to Joseph Francis for this information :
I purchased no. 1617 flatcar with tractor & wagon. The black flatcar is stamped "CHICAGO LINE R.R. 1617-A" in white sans-serif letters on the side; the bottom has cast into it:
M T S I
PART. NO. 72249
MADE IN KOREA
The (blue) modern tractor and (red) 4-wheel wagon are both stamped CHINA. They are cast pot metal with rubber wheels, held onto the flatcar by elastic cords. The yellow, black, and white box, which has a simple drawing of the Chicago skyline (Sears tower on the left, Hancock on the right), has "P.O. BOX 2176 LaGrange, ILL. 60525" and "ASSEMBLED IN USA" on the side.