@Arnold D. Cribari Great topic Arnold, another reason I kick my self for straying away from Lionel track. Besides not being able to run operating cars; any PW cars with solenoid type couplers are shelf Queens. I do have a horse car and a milk car on a siding.

Take those cars off the shelf and use them! This year (after a 12 year break) I pulled my stuff out for Christmas. I run MTH DCS, and Realtrax (no comments here about it) and I incorporated (I think Walt does also) much of my postwar stuff from the '50's. I have two coal loaders, dumping coal from the cars shown in Arnold's first video. I install the RT UCS track, works great. I have the Lionel log loader (forgot the number, green/red roof w/ the chains that lifts the log) also w/ a UCS track.
Your cattle loader and milk loader present two problems for you that I solved, and you might be able to do the same thing. The milk platform is problematic since it has that 90 degree bend on the outside edge. I have two of them. One year, I took a band saw, and sawed of the sides that interferred with the platform, and gave the MTH UCS the shape of the older O Lionel UCS track. Worked great.
Another year I decided to use an MTH UCS track, so I took a vise, put the platform outer edge in it, and bent it out flat - it fit under the UCS track. This year, I used 4 milk cars and started to put out 2 UCS setups....but then thought, "one platform on one side of the UCS track, one on the other side, and no matter which side the doors are on, the cans will leave a car, and wind up on the platform!
Unless the aux voltage to the UCS track is too high, then the cans get tossed, flip and....oh well, spilt milk! I do find that it is of importance, to use AUX transformer power to regulate the voltage to each track. Some cars need more, some less. This year, I hooked up two UCS tracks to each coal loader. Tested the loaders and the cars, all worked perfectly. Same with the log loader. New Year's Day, I had the first group over to view the train setup for 2024. (Ok, you sharp guys caught that I did NOT get the trains up for Christmas, despite starting Nov 1st. I just don't work as fast as I did 12 years ago!)
Back on topic. I used some older Lionel 1033 transformers for the UCS power, they were perfect and dumped the cars every time. EXCEPT, Jan 1st. I had to "manually" dump my loads, then run the loaders.
I figured out what happened, by now most of you have also: the cars were empty! The coal load and the logs required more power - thank you Tim Allen! Next day, I used different transformers to feed the UCS tracks, and it has all worked perfectly since. Only thing is, the milk cars are a compromise. Some dump great at the voltage I set, some don't, so I average it out instead of changing it for each car.
Like I told a parent who was watching the logs dump, "I have those features on here to entertain the kids!" He replied back, "They are great for entertaining the adults also!"
As for your horse loader, you have NO idea how many hours I have worked in the last months to get the cattle car and platform working right. See the post below!!
I actually have a video of 5 cows that I did manage to get to leave the platform, enter the car, and exit the car - TWICE, before one of them keeled over. Maybe one day soon, I will post it.
Your horse loader is MUCH easier to master, by the time the got to the horses, Lionel saw that no sides on the tray in the car, let the cows tip and die. Inside your horse car, the sides are high to prevent this. They also made the sides on the "corral" high enough to hold them up. You should have no problem getting yours to work...if you try the following.
I don't have a horse loader, but if it works like the cattle, there is the corral/pen and on the Lionel track the cows have two slabs of metal that make contact to the shoe on the car. The car/pen tie to either the track voltage, OR a separate power source. I think the best way to get the cattle car to work, is to use a separate power supply for the track/car and one for the pen! A single power source for the cattle means high voltage to get the car to work right, equals too much voltage for the pen...the cows practically pole vault off of the pen/corral.
After I take my layout down, I am going to test that theory. I found that the UCS track will operate the car, and another power supply can operate the pen...two voltages for two uses. You may not have to go that far with horses, but most of us have had no luck getting those stupid cows to cooperate! (Maybe they just don't want to ride the rails to the slaughter house!!??)
HOWEVER - IF you really want to use Lionel O/O27 track, MTH made adapters to fit them to realtrax. Lionel probably did also. I used them this year, next year I am using UCS MTH, if I am here to put trains up next year!
At any rate, sorry for the length, but I want you to entertain some young'uns with those operating cars.!! You will have a blast. They are well worth the money and aggravation, once you get them to work. I am sure you can do it.
Best of luck, Greg
COWS.... https://ogrforum.com/topic/acc...2#188804206121794852
MILK PLATFORMS. on the left, I can get you better pict if you want it.

Noisiest thing you will ever install:

LOG AND CATTLE LOADER, early on. The American Flyer coal tower at far end.
