Would it be ok to have a track go up 18" over 18’ of track?
Sure, why not!!! [swg]
At 8.33% those trains coming down that grade would pick up speed and derail into a heap on the floor busting apart. As you sit there with you mouth open wondering what you have done, remember to please take video for our future enjoyment. [:-,]
Seriously, the answer is “Not if you intend to run your trains on the that track.”
I believe that works out to an 8.3% That’s pretty steep. You probably want to keep it under 4%. Even 4% is pushing it. Kicking Horse pass used to have a 4% grade and it caused a lot of problems. CP Rail eventually build the spiral tunnels to get it down to a more managable 2%. An 8% grade is going to cause problems with traction tires, slippage, couplers and if there is a break away, the cars that break free are going to be really flying by the time they get to the bottom of the grade.
That is a 8.33% grade, the Lionel trestle sets are about 4% with “O” & about 4.5% with “O-27” track.
Rob
So, the max that I should raise the track over 18 feet is about 9 inches, right?
I personally would rethink to about 5 or 6 inches. but if you need to go higher I would look into maybe building a gradual curve track where it could do the hight you want but maybe go over itself 3 times. You say you have 18’ so I take you have a fair size layout so you should have room to do that. Make it a mountain with the train going in and out on its way up.
You could use an O-72 helix with three “wraps” to get you to your elevation difference. This is not going to be easy or cheap to construct. Multi level layouts do have a lot of visual appeal but trying to get trains fron one level to another can be challenging, especially when you are talking about 18" differences in elevation.
The alternative is to build a second elevated loop and run 2-trains.
Kurt