About 10 yrs ago there was a Japanese modeler who entered a HOn30 logging diorama about 2' in diameter,
which was a loop with one siding, in a regional NMRA convention.
This diorama had a working 2 spool skidder. The lines came up from underneath the diorama powered by a geared motor.
The skidder also had a working smoke unit which I think that either was a small Suethe unit or perhaps it was scratch built.
I don't think it had sound as back then about the most used sound system was made by PFM, but today sound would be a must.
What you want to do is very doable and the only problem I see is solving the problem of the logs swaying as you lift them.
Also you could have problems in hooking the cables to the logs unless you do it manually.
I spent a few hours last night looking for the article in building the diorama but couldn't find it again.
If I do I will pass the link onto you.
Also years ago I grabbed a minute or so of a Willamette 3 speed yarder operating on the West Side Lumber Co. out of a video,
as I really liked its sound and sent it to ITTP and they made a special sound module for me.
It is listed on their website as a steam winch, which in reality it should have been labeled as a 3 drum logging yarder.
Years ago I purchased a small voice recorder that were being closed out at KMart.
I think they were designed for use for a shopper. You would record your shopping list on this small recorder and then use it in the store.
You could use them over and over. As I remember the sound chip could record up to a minute of sound.
I purchased a few of them as they were so cheap.
1 - Make sure that you can't wind the line too far. This WILL destroy pulleys and your rigging.
This means that you will need some type of a limit switch set up that will kill power to the winch at both ends of the skyline run.
I know that Prof had to rebuild the rigging when the limits failed once.
I'd recommend not relying on the Mark 1 eyeball and manual control, if you get distracted the results could be catastrophic.
2 - Originally it was hauling a log, but sending a log back to the forest didn't make much sense modelling wise, so the skyline travels empty.
If you are prepared to use "the big hand from the sky" to load and unload your logs then this isn't an issue.
But "hands free" pick up and drop-off of your logs is a whole different ballgame.
Unanderra in oz
I wanted to show you some more of the work on animating the steam donkeys.
The first one I worked on is the donkey engine at the log dump.
Rather than powering the winches electrically I chose to use a manual Cable to lift the logs or lift the unloading mechanism at the log dump.
Here you can see the shrink tubing I used to conduct a fine wire cable from the first spool of the loader,
back to a hole extending up into the water tank of the loader.
The Cable is threaded up through the water tank and out the water fill spout.
It's end is affixed to the water tank hatch (cap) which can be pulled to move the cable.
The cable goes from the first spool of the loader to the pulley in the block on the gin pole.
It is connected with a hook and swivel to the piece of railroad steel (lifting bar) that will be attached to chains
(awaiting some parts before they are attached)
that will nudge the logs off the log cars and on to the dump.
When the bar and the chains are on the ground the cable pulls the water hatch (cap) closed on the tank.
When the bar and chains are hoisted up the cap and wire cable are pulled through the tank like this.
Hope this makes some sense and the pictures helped.
I hope to make some pictures and maybe a video showing how the logs are unloaded using this mechanism in the future.