Sorry to necro this thread from so many years ago, but I stumbled across it and was really interested in sharing some extra information.
I actually work at Amsted Rail (ASF-Keystone), and we produce couplers that look just like this. This may be a previous pattern number as I don't recognize EK310C. However, this coupler looks almost identical to an AAR E type coupler known as an SBE60EE, which is one of the patterns that we produce. All of the letters and numbers in the pattern mean something specific and are designated by the AAR. There are 2 other couplers that look similar to this - the E60EE, which is the base type coupler of this series, and the SE60EE, which has 2 support shelves (top and bottom). There are also other series of couplers out there that look different and have a different series number (SBE67DE, SBE68DE, SBE69CE, etc) as well.
For the SBE60EE, here is what the letters and numbers standard for...
S - Shelves
B- Bottom shelf only
E- E Type Coupler Head
60 - 60 series coupler
E - this letter is like a "revision" letter. Whenever a major change to the design is made by the AAR, this letter changes. E is the current AAR pattern revision letter.
E - E Grade Steel. E grade steel is an alloy designated by the AAR and has specific chemistry ranges for the elements. Couplers, yokes, and knuckles are all made with E steel.
So you can see that for the E60EE pattern, there are no shelves and for the SE60EE, the B is removed because it has a top and bottom shelf. The shelf is that little thing hanging off the bottom of the coupler head by the knuckle (at least I think I see a shelf in the photos). Support shelves are used to help prevent detachment of the train cars. The two knuckle throats slide up and down each other from variation in track flatness. The shelf prevents the knuckles from sliding off of each other from a bump. The SE60EE, which has two shelves, is mainly used on tank cars. The extra shelf on the top serves the same purpose as the bottom shelf. Tank cars use this pattern because they don't want to risk a detachment from the top (which is really unlikely to happen) to somehow cause the tank car to get punctured. Some cars that ride lower to the ground can't have shelves because it would drag, so they would use an E60EE coupler. I don't believe there is a such thing as a top shelf only coupler, or at least I've never heard of one.
As for the PATD panel, that is something required by the AAR, and the location of that is actually designated by them. All E60 type couplers (from all AAR certified manufacturers) have that PATD marking on the shank in that spot in a recessed panel. I have attached a photo of a top view of an SE60EE coupler made at our foundry (it's still in rough condition from shakeout and hasn't been worked up yet). The shelf that you see in the photo (which has the AAR letters on it) is the top shelf. They are called bottom and top shelves based on where they are on the coupler in running position on the train (top of the coupler or bottom of the coupler -DUH!
) You can also see the recessed PATD panel in the photo.
As for the model itself, we have a few of those in our plant as well. I think they made them a really long time ago and gave them out to employees as a gift for years of service maybe. I'm not too sure on that to be honest, and I don't know what their worth is. I always thought they were really neat and enjoyed disassembling, reassembling, and operating them (unlocking and throwing the knuckle) like a real coupler.
