Should be plenty to allow for the clearance - a 1.5% grade over that distance is actually 3.9" of rise. A 2% grade is more than 5" - enough to clear benchwork rather than just an HO scale bridge. The 42: radius makes for lots of length to keep the grade % down.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Have thought about it some what and need to see how tall the beams are. But like I said, this was more of a math test for now.
Ken
I hate Rust
Did you account for the thickness of the bridge and track, or do you need to go a little bit higher than the 3.5"?
I was pretty sure I was right, thank you all for checking for me.
Yeah it's actually a little lower grade, so you should be fine. 'Only' 263 inches of length - that's almost 22 feet of track! I barely have that much on my main line on 3 walls of the room.
Length of run is simple - 2 x radius x 3.14. If you want to do it in your head use 6x radius, knowing the number will come out low so any grade will be less than expected.
I got 241.9" (84" diameter x pi x330/360). 241.9/3.5 gives 69" per inch of rise or 1.4%.
Sounds close to me.
A 1.5% grade is a 1.5 inch rise every 100 inches, so it looks like you are good.
Elmer.
The above is my opinion, from an active and experienced Model Railroader in N scale and HO since 1961.
(Modeling Freelance, Eastern US, HO scale, in 1962, with NCE DCC for locomotive control and a stand alone LocoNet for block detection and signals.) http://waynes-trains.com/ at home, and N scale at the Club.
Still more doodling, this time it is based on this.
I want to make sure I am doing the math correct. track at the top starts around a 42 inch radius turn (Mountain) climbs 3.5 inches for 330 degrees and crosses it self.
If I have done the math correct the total run of the turn section only is 244.88 inches, and with climbing 3.5 inches the grade should be 1.45% Does the math sound correct?
I know there would be more drag with it going around the turn. Right now I am just checking the math.