Don't know if they are the same as mine but I had the problem, my engines were just sitting for several years. Found the couplers had desintegrated and fell off, the 2 rear on the A units and both on the B
The were non operating. I reverse engineered them but added reinforcement. I decided to use PETG filament which is pretty strong and 3D print them. They worked and tested them under some heavy loads and no problem so far.
They do not have the centering springs anymore but it does't matter to me as long as they can pull and don't fall apart or come uncoupled.
I've been in contact with Atlas about these, they say you can get them but have to by an assembly, but I don't need any more problems,
I can give you the STL files that I made to 3D print them. if you don't have access to a printer and want them we could arrange something else.