The pier or trestle sets I've seen are actually adjustable. They hook on to the bottom of the track, but the grade you end up with will depend on how closely you space the supports. Generally, though, you will need a support every 4 1/2 inches (half of a snap-track span) on curves, just to keep the track supported. You can spread that out a bit more on straights, but for long spans you might consider bridges or the Atlas pier girders for additional support.
If you are building a full layout, consider the possibility of going down as well as up to get that 3-inch clearance. Also, remember that you can get the illusion of grades by sloping the scenery the other way. This will also be easier on your engines, and let you pull longer trains.
It takes an iron man to play with a toy iron horse.
Are you thinking HO or N? If your space is only 40" wide you will have to use 15" radius for your inner loop. Are you planning to have one track pass over the other? Since you don't have a full 8' length I'm not sure a regular incline set would be enough. Not familiar with what degrees of slope WS has, but measure distance available to climb from base level to crossover point. I believe you need about 3" clearance from top of rail to bottom of obstruction above for HO. divide 3" by the number of inches you have available for the climb for your grade %. If you just want one to rise and fall for variation, you can use most anything to get you up and down. Sorry I don't have a pier set to measure the incline for you.
Good luck
I am making a small layout for my 6 year old out of Life Like's Power Loc track. It will have two tracks on it so that he can get a feel for handling more that one train (plus it will look cool)... :)
I see some Life Like sets (as well as others) that have a bridge and pier set included and I need something similar for my son's layout.
I was thinking I could use WS Incline system....and get some experience with it, but I don't know which size to purchase.
In your opinion, what % incline do the bridge and pier sets that one can purchase (separately or in a train set) represent? I'm thinking 3%, but I'm not sure. If anyone could help, I'd appreciate it.
I will be covering it all in astro-turf. Remember...it's a small 40" x 72" layout for my son's room.
Thanks,
Mike/Nightshade