So first off, hello everyone. I played openttd for a while and switched to simutrans perhaps 6-7 months ago, and am really liking how detailed I can make my networks
On to my question!

As you can see, my intent is to create an area of siding that can be used as waiting track. Currently, I have tried to set up a system using pre-signals, but I must not understand how they work. None of the trains will make their way to the clear siding--I have made sure that there are no way points on the northbound track, so its not an issue of them following waypoints. How do pre-signals work, and how do I set up a system such as Ive described? The chooseplatform signals work wonderfully for stations, but seem to not apply to track with no station tile. That would defeat the purpose of the waiting tracks. My intention is to create railyards at large junctions and large stations where inbound trains can wait for a free station platform.
An easier question: How do you change the signal drag density?
EDIT: Oops, the image didnt come up the first time...