Okay when I got a minute I headed to the basement to get out my C39...
ridinshotgun, you have to open up the Scale Trains box and assemble the 1015 shanks into the box. You cannot use the 1015 box from MT. A lot of manufacturers are doing it this way now (although usually with factory installed 1015 clone shanks.) Also the ScaleTrains box looks better.
My C39 coupler boxes do not have any glue or any extra parts attached to them. They are just better looking versions of the MT box, designed to fit their loco's pilot.
I don't know if I'll have the bandwith to post pictures, but I suspect Pete would recognize the design as similar if not identical to the turbine box.
The design of the Scale Trains coupler itself is, well, interesting. But I'm not really motivated to go into detail about something I'm basically going to discard.
I opened mine back up last night and the air hoses were most definitely glued to the ST draft box. I had one that must have come off last time I pulled the coupler box out and the second was still attached until I pulled the box and tried to separate the lid. There was definitely glue used that must have seeped in because it took a good bit of effort to separate the box lid and the air hose went off to parts unknown. I was able to fit the 1015 shanks into the boxes but like you I had one that was sticky. It was the one that I had trouble opening up before but a little scraping with an xacto cleaned it up. Probable glue or flash in the box. Only problem now is that the rear coupler has a noticeable set back much further than the front coupler. I ran it around with some other locos and while not touching I am thinking it will cause some problems if used with some of my close coupled cars. Weird that they had the front pocket designed different from the rear. I guess I find out this weekend how it actually runs with my close coupled cars.
As far a lot of manufacturers doing it this way I'll just have to agree to disagree. Of all the locos I have purchased in the last 18 months, including Atlas, FVM, Rapido and Kato not a single one has done it like ST. Each one was an exact fit for the whole 1015 system or already had the 1015's installed as new. Either unscrew a screw and replace or pop a spring and replace with a screw. Pretty simple and easier than having to crack open two boxes and replace internals and having springs flying all over the place.
One good things is that at least the couplers in the C39 were easier to install than the carbon black hoppers. Those were a major PITA to install and the MTL still don't work right 100% of the time because of their failure to catch the mis-molded box design.
