This car belongs to a group of conversions that are not quite straightforward as there is no underframe at the ends that the new couplers can be attached to.
As before I have used the Micro-Trains #1015 coupler. To attach the couplers I have made coupler plates from 0.5mm (.010in) brass sheet that are glued to the car using epoxy.
The car sits a little high with 0.5mm thick coupler plates when the coupler height is correctly adjusted (I've put thin washers between the trucks and the body bolsters). Instead of making the plates thinner it is possible to file the lip extending under the end sill thinner as shown in fig. 1.