Sackbut wrote: Thanks, I'm thinking 90 so the overhang should be a problem.....When you say "centered on the underpass" I assume that you mean that is roughly one half car length each side of the underpass....and not a car length on either side?
Thanks,
I'm thinking 90 so the overhang should be a problem.....
When you say "centered on the underpass" I assume that you mean that is roughly one half car length each side of the underpass....and not a car length on either side?
Yep. I think that should work unless you are only clearing by microns. Since you have to ease into the climb you'll be out from under before you hit, I should think. Of course more wouldn't hurt.
Jeff But it's a dry heat!
Sackbut wrote: I had already checked that and your memory is good...BTW....
I had already checked that and your memory is good...BTW....
It's amazing what sticks in the brain cells. Unfortunately there is the stuff that doesn't! I think pcarrell already answered your question, if you are gentle you could probably cheat a tiny little bit. Getting under the underpassI think you only need to be flat for one length, centered on the underpass. One other thing (I learned this one the hard way)... if your crossing is at other than a right angle especially, make sure you allow for the overhang everywhere it comes into play, and not just at the intersection. There is width and depth to everything!
Ahh, that's exactly what I needed.....pretty much what I was thinking but needed to confirm....
THanks for the help....
Sackbut wrote: Well, actually I'm not asking about vertical...... I had already checked that and your memory is good...BTW.... What I'm trying to figure out is how far from the overpass I can begin to climb.... I know there is a factor of the incline causing clearance problems if part of the car is still on the incline while the other end of the car has begun to go under the crossover....
Well, actually I'm not asking about vertical...... I had already checked that and your memory is good...BTW.... What I'm trying to figure out is how far from the overpass I can begin to climb.... I know there is a factor of the incline causing clearance problems if part of the car is still on the incline while the other end of the car has begun to go under the crossover....
The answer to this question is the length of your longest piece of equipment (before you begin the transition).
THe other issue was once I reach the 2" height how soon (length wise) can I begin the descent....I know there needs to be some 'flat' at the top and that you can't go up and immediately down....trying to figure out how far/long that 'flat' has to be..
For this one you want the flat part to be twice the length of your longest piece of equipment. The reason is, you don't want the couplers between two cars to have a situation where one is going up as the other is going down. This may cause them to uncouple. Thats the same reason you use transitions too BTW.
Thanks
You'll want that to be a strong 2", as you'll need a little space for roadbed. If I'm remembering right the NMRA recommendation is 1 21/32" railhead to obstruction. I don't know if that accounts for doublestacks, or was before their time.
You'll need a 2" rise to clear the lower level. A 4% grade is considered by most as a maximum grade. That means that you'll need 4' to rise 2", plus the transitions at the top and bottom of the grade. Call it 5' of track to make it happen.
Here's the thing though. That is a maximum, so a single loco isn't going to pull many cars up that grade before the wheels start slipping. How many depends on the weight of the loco, if it has traction tires, the weight of the cars, how free they roll, and how many of them.
A 2% grade would be much better. That would be a 2" rise in 8' plus the transitions. Call it 9' or so.
The transitions are necessary and should "at least" as long as the longest piece of equipment that you'll be using.....longer is better.
Hope that all helps!
I'm building a Chirstmas figure 8 over and under. Haven't done this in years and have a couple of questions:
1. Coming out of a climb how much distance before you can begin a descent without encountering problems?
2. How much straight track is required before going under the crossover?