The screensaver will switch from an active train because it arrived at a stop to a train that is idling in a stacker.

The mod should only switch to a train that has changed state from waiting-at-a-station to moving. Does your stacker by chance have stations in it?

It does not

Edit: I will look again when it happens, but it seems odd to be watching a train idling in a stacker regardless

Thanks for that info, I completely agree it should not be switching to a train that is idling in a stacker, or idling at all for that matter. I will run some tests to try and see what's going on.

After watching again for awhile I did not see it switch to a train in a stacker. However it does follow a train into a stacker and stay on that train for a long time.

That's good to hear, as I have so far been unable to replicate being switched to a train that's already idle at a stacker. Basically, the mod works by listening to train state changes and updating the camera to follow any train that just left a station. So if the camera is following a train and it pulls into a stacker, the camera will stay on that train until any train changes state from "waiting at a station" to "moving along the route". That means that it's possible the camera ends up just watching a single idle train for a long time if no trains leave stations during that time. If you'd like, you can set the "Signal Timeout" setting (player mod settings) to a low value- it's set to 30 seconds by default to prevent the camera from switching to a new train if the current one is only temporarily stopped along the route (mainly helpful for large train networks, when trains are constantly/very frequently leaving stations), but you can set it as low as you want to (or set to = 0 to disable it and always follow a new train if the current one is stopped for any amount of time)

I've updated the mod so the signal timeout setting is much more precise