Val,
I have a couple suggestions that might work for photography, while still allowing you to have the advantage of automatic uncoupling. 1. When I install Kaddees, I assemble the coupler in it's box, then I use a 2-56 screw and nut to hold everything together. I cut the "ears" off of the box, unless I need to use them to mount the kaddees. So far I have not found any plastic model that needs them. I suspect that they are used on wood kits, but I don't have any of those. Finally I use Testors liquid plastic cement to glue the box together just around the edges, being careful not to get any glue inside the box of course. Once the glue dries, I remove the screw, and my Kaddee is ready to be mounted to a car as an assembly. If you also get some dummy couplers like those from MDC/Roundhouse, you can mount them in spare Kaddee boxes and glue the boxes together. Then you just change out the coupler assembly for photos. You would not need to change out all of the couplers for photos. I think just changing those couplers on the ends of rolling stock that aren't coupled to other cars would be sufficient. 2. The other method would be to build a few cars for photo purposes with dummy couplers, and complete air brake hose and glad hand detail. These cars could be extremely highly detailed if you like since they won't be operational. Then you use these highly detailed models for photography only. They would be removed, and perhaps put on display in display boxes when you are operating your trains. I have found that many of the kits from Lifelike p2k, Intermountain, Red Caboose, etc. have so much under body detail and detail around the couplers, that they don't operate very well, anyway. I hope this thing didn't get too long for a quick reply.
I have a couple suggestions that might work for photography, while still allowing you to have the advantage of automatic uncoupling. 1. When I install Kaddees, I assemble the coupler in it's box, then I use a 2-56 screw and nut to hold everything together. I cut the "ears" off of the box, unless I need to use them to mount the kaddees. So far I have not found any plastic model that needs them. I suspect that they are used on wood kits, but I don't have any of those. Finally I use Testors liquid plastic cement to glue the box together just around the edges, being careful not to get any glue inside the box of course. Once the glue dries, I remove the screw, and my Kaddee is ready to be mounted to a car as an assembly. If you also get some dummy couplers like those from MDC/Roundhouse, you can mount them in spare Kaddee boxes and glue the boxes together. Then you just change out the coupler assembly for photos. You would not need to change out all of the couplers for photos. I think just changing those couplers on the ends of rolling stock that aren't coupled to other cars would be sufficient. 2. The other method would be to build a few cars for photo purposes with dummy couplers, and complete air brake hose and glad hand detail. These cars could be extremely highly detailed if you like since they won't be operational. Then you use these highly detailed models for photography only. They would be removed, and perhaps put on display in display boxes when you are operating your trains. I have found that many of the kits from Lifelike p2k, Intermountain, Red Caboose, etc. have so much under body detail and detail around the couplers, that they don't operate very well, anyway. I hope this thing didn't get too long for a quick reply.