Märklin boxes
Here is a summary of the various types of packaging used by Märklin for their products. The style of packaging is often used to date a particular item into a broad range of years. Paper products, including cardboard boxes also usually have a printing date on them that gives the month a year in which the box was printed. This provides a maximum age for the box. These packaging styles do not apply to Märklin's 1972-introduced Z scale product line.
Wooden
With straw packing.
Brown
The early boxes were brown card, held together by staples
Red
Locomotives and wagons came in red boxes
Light Blue
was used for locomotives, wagons and track. Initially locomotives were held in place by pieces of cardboard, later by a styrofoam insert
Middle Blue
Orange
Build up kits were in Orange boxes
Sets
Initially had a nice painting on the box
Yellow
Used for Accessories
Green
Lime Green used for special track items and dark green for some rollingstock
Multicolored
Locomotive boxes lost the painting of the prototype and instead had a multicolored box that did not depict the contents of the box.
Blue, Red & Orange
Later a transparent front allowed one to see the locomotive...
Blue and white
was used for almost everything...
Blue Plastic
Blue and transparent plastic with a cardboard sleeve was used for 3008 and 3009 locomotives only
Gray
Signified an item in the Digital line. There seems to be some variation in the Gray here too...