Marx plastic couplers: when?

[arkady]

Thank you, JamesP, that information is appreciated.

 

[JamesP]

Marx started putting plastic knuckle couplers on 6" tin starting in 1953.  Although 6" tin w/ PKC in train sets were phased out in the mid to late 50's, it is thought that individual 6" cars may have been sold with PKC's through the early 60's. 

If you are interested in Marx 6" tin, Walt Hiteshaw has a very thorough reference CD available through his website:  http://www.toyandtrainguides.com/marxtin.htm

[arkady]

Does anyone know roughly when Marx started putting plastic dummy couplers on their 6" freight cars?  I was given several of them for Christmas, and I'd like to have some idea when they were made.

Thanks.