after behing routed to your thread, and after trying unsuccessfully to use the prog signal for what i want... i d like to get some help

I m trying to make a siding(with a waypoint) giving the ability to stop a freight train when a faster train enter the parralel track of the siding... at the same time i d like to keep the fast trains running smooth by keeping the same signal distance on the fast lane (there is often two or more fast train following each other cause slowed down for a while by the slow freight train)...
Any hint on the programation i should set to get same result as in my exemple down there(link) would be very appreciated

this is my exemple(with path and normal signals), wich works perfectly but is very ugly. I d like to make it look more simple and realistic thanks the prog signals: http://www.tt-forums.net/viewtopic.php? ... &start=160
follow link and scroll down a little until you see this:
Coal train is in front (and enter the siding reserved for slow and unautomated timetabled trains).
Wali Transport, 20_08_1975.png [240.43 Kio]
The ICE train is entering the fast lane and by passing the first path signal make the simple signal go red at end of the slow lane... this signal willl stay red until the Ice trains is gone in front.
Wali Transport, 20_08_1975#1.png [240.91 Kio]
following moment where the ICE train is now way in front entering a tunnel, another ICE train following enough closely to keep the red signal on the slow lane... and you can even spot that a slow local passenger trains is also entering the fast lane and will keep the red signal for the coal train until its gone in front

Wali Transport, 20_08_1975#3.png [241.11 Kio]
Thanks in advance
Romazoon