need some help please!

[Anonymous]

hello again, sorry for the dumb questions, but can someone explain in lamens terms how to figure elevation in HO scale? i have plans to run a single branch line over a double main line. i measured the height of my tallest car on track and cork, and i figured about 3 1/2" should clear. im not sure how many feet i need to get this up and down, so any info or links is appreciated. thanks!

[detting]

The formula is pretty simple:
rise/run
If it take you 100 inches to reach that 3.5 inch peak then:
3.5/100 or 3.5% grade.
As the grade increases, your engines will pull less. There was a good article in an early 60s MR that explained this stuff, you may want to track it down.
As for how long to make this grade:
In real life, most trains will require helpers when the grade exceeds 2 or 2.5%.
The majority of prototype grades never exceed about 4.5%.

Later...

[Anonymous]

Stephen,

Also bear in mind that if your grade is on a curve, it makes it even more difficult for the engines to pull... A 2.5% grade on a 18" radius feels like a 5% grade on a straight (more or less...). So if you intend to loop around in a figure-8 type plan, you will be pulling very short trains, or you will need more than 100 inches of track run to gain that elevation.

Andrew

PS - Could you also please use more descriptive titles for your posts? Most everyone here wants a question answered sooner or later, but giving a hint what it is can help the "responders". By the way - there are no dumb questions!

[cwclark]

yep...that's about right...a 1" rise every 96" of track is a 1% grade...2" for every 96" is a 2%, ect....there is one stipulation that you need to be aware of...if you plan on running the container cars i'd go to a 4" height...3 1/2" will not allow those high containers on the container cars to clear the 3 1/2" height....Chuck[:D]

[Anonymous]

Steve,

Grades are a sore spot for modelers because no one wants to take a long distance to climb. I would suggest that you try to limit your grades to around 2%, if you can. To climb to 3.5" at 2% you will need almost 14 feet of run. If this wont fit, I might reconsider the track plan. The exception to this is logging or shortline railroads where short trains and steeper grades were common. The mainline class 1 prototype tried to avoid grades of more than 2% and many grades in this range used helpers.

The reasons for using gentle grades are:

Operation: locos can't pull long trains up steep grades. Nothing is worse than to discover that you have to double head to pull 5 boxcars up a grade. Some locos barely make it up steep grades by themselves without wheel slip.

Scenic: steep grades willl look funny when you try to put buildings and scenic items next to them. A building next to 5% grade will look out of plumb. Do you set the loading dock of a station or freight shed on the track angle or level? Either way it won't look right.

I speak from experience. On my last railroad I had 5% grades.....My current layout has 2% maximum. The last railroad was a Marklin layout. Marklin locos have traction tires so pulling power wasn't an issue. Even so, I could never solve the appearance issues..

my 2 cents,

Guy