Percentage of grade increase

A 1% grade is 1 inch per 100, a 3% grade is 3 inches per 100. The math is pretty simple. Remember any curves on a grade increases drag, the sharper the curve, the more the drag.

A 3% grade would rise .3 inches over the length of a traditional 10" piece of straight track.  I suggest doing a forum search on "grade".  Quite a few threads about this and lots of info on the ability of trains to handle various grades.

Bill

How do you make the transitions, both at the start of the incline and at the end?  Both need to be gradual to avoid derailments or uncouplings.  The transition at the top of the climb where the track forms a crown seems to be the harder one to do if the grade is 2-3%m from my limited experience.

One thing that can be really constricting in layout design is to have a flat one plane layout and then add an over/under grade to it.  Consider incorporating any grades at the outset of building your RR.

As you  develop your plan determine the area where you would like your over/under to occur.

Going into this we are working on your desire to work with 3% grading.  For a 6" rise you will need apx.16' 8" of travel.  (let's talk rough numbers here, we can do vertical curves later)

Then within the foot print of the real estate you have available,  proceed to develop three levels.  These can be overlaping levels, just develop three levels.

For the sake of discussion start with the middle level and let's say this is the main level or zero datum.

To do the over under run a right of way down 3" from datum for a distance of 8'4" and run another grade up hill from datum 3" for the same distance of 8'4" and you will now have the over/under feature in just half the length.

This idea can be fudged to go down 2" and up 4" with the correct lengths and achieve the same type of advantage.

You can also use this idea to lessen grades. 

When I design a layout I start with all the over/unders in mind in conjunction with curve radius and severity and let those factors determine the ultimate right of way routing.  The location of over/under are very pivotal in layout design. Too steep of a grade can be a real discouragement. Forget the prototypical pusher stuff IMO, it just gets real old real soon.

On my mainlines, I use no more than 2.5%.  That means 3 inches rise in ten feet of track.

I like to use the approximation based on 8 feet, 96 inches:

4% is a rise of 4 inches in 8 feet (2 inches in 4 ft, 1 inch in 2 ft, etc).

3% is a rise of 3 inches in 8 feet (1.5 inches in 4 ft, etc)

2% is a rise of 2 inches in 8 feet, and etc. 

This is easy to work out in your head as you plan.  And it is also used by Woodland Scenics in their foam risers.

And use an easement going into and out of the grade:  use 1 to 2 feet of 2% leading into a 3% or 4% grade.   Otherwise, the sharp change from level to 4% will cause steamers to lose some traction as middle drivers lose contact with the rails at the point of inflection, some diesels will make contact between the truck frame top and the bottom of the locomotive frame.

I allow up to 3% on straight (tangent) track, and 2% on curved track for the reasons others have already noted.

All above is very useful now that I need it.  However, I am doing a grade on a logging

and mining branch that will have small locos moving slowly, with short trains, nothing

bigger than an MTH Russian Decapod, and it will just pick up completed trains...

switching activity will use smaller locos as now seen.  If anybody made it, I would use

a cog road to save space.  It takes 25 feet of track to gain 6" height at 2%.  I have

thought about using Otto Mears' Silverton RR covered turntable to avoid that 2%

25 foot length which requires a wide curve.  For slow moving switching, is a steeper grade practical?  Anybody done any hill climb tests?

A good thread on grades/grade calculations started Oct 2/2013.  Click on the underlined phrase to link.  Thread title is Grade questions.

Woodland Scenics makes transition grade risers.

If you run long trains or metal cars, your engines will notice the grade.

If you have a decent locomotive and fairly light cars, you can consider steeper grades.  My MTH Climax will easily do a 6% grade with five IDR log cars in tow.  The major issue I'd be considering is on a long grade with lots of cars, you may run into overheating the motor(s) or electronics.

What I'd do is setup a test scenario with different grades and just run various consists up to see what your limits are.  The traditional limits I've seen published may be somewhat dated in these days of modern locomotives with traction tires. 

Obviously, coming down is not a big problem.

Mining operations usually have steeper grades anyway so whatever you decide will most likely have a prototype somewhere.

The Woodland Scenic risers and inclines are a great product.  

--Greg

An easy way to measure grades is to use a 2-foot long bubble level. Set the level on the grade and raise the lower end until the bubble shows level. Then measure how far off the track the lower end is. Every 1/4" equals 1% of grade.

• If the lower end is 1/2-inch off the track, that's a 2% grade.
• If the lower end is 3/4-inch off the track, that's a 3% grade.
• If the lower end is 1-inch off the track, that's a 4% grade.
• etc.

Easy.

Rich,

Just to be precise, wouldn't that make a 4% grade into 1" per 96", rather than 1" per 100"? That would cause grades using your method to be understated by about .04%.

Although that's not much of a difference, it would very likely upset the "rivet counters" among us.  

Also beware of the dreaded "transition piece" which may cause steam engine pilots or other low items to short on the center rail.

We're going to be pushing the grade max when the "mountain division" goes in ... have to do a 3.5% grade minimum ... with a curve at the top.

Thinking the big electrics and the all-powered ABBA Atlas Fs will manage to get the train up the hill if it isn't too long.  And we can always add a helper to the rear and run it in a lash-up with the leading locomotive.

It's the theory anyway ... and in this case we don't have a choice about the gradient.

Just to be precise, wouldn't that make a 4% grade into 1" per 96", rather than 1" per 100"? That would cause grades using your method to be understated by about .04%.

Although that's not much of a difference, it would very likely upset the "rivet counters" among us.  

If someone really thinks that having his grade percentages off by .04% is a problem, then that truly IS a problem...for the rivet counter, not me.

Clarification

Actual calculation 1"/96" x 100 = 1.0416%.  The .0416 is a bit steeper than 1"/100". which is 1%.  A nat's eyelash, maybe.  

Rich, there's a little tiny rivet in the corner of the tender that you missed, that makes 2,147 total.

OK, Gunrunner...two can play that game. 

How many notches are there on the 765's throttle quadrant? Hint...the model is not accurate. In fact, it's not even there!

Call the Rivet Counters! It's a conspiracy! 

Can't find the reference at the moment, never can when I'm looking, but, I believe for class 1 railroads the transition cannot EXCEED .25%/100'; thats 3"/100'. It actually might be less.

3"/100 feet for Class 1's?  Good thing I am now building a branch off a short line and

trying to get 6" in less than 25 feet (which = 2%).  I doubt if the Elk River logging

road recently posted on here came anywhere close to either number.  I would like to

have 2% but not in 25 feet.  I don't think it would be too hard to build a model

cog loco (commercially!!)....just put a cog in the center of one of the axles, wire it to the motor so it can pickup, and, for backup, add an easily replaceable roller or slider (as it is going to wear out fast rubbing over those notches cut in the center rail!).  (and wear sound deadener earmuffs when you run the cog road...there is going to be more clickety-clack than you can stand) Well, time to redraw this again....cramming

a square peg in a round hole.

You misunderstand Rich, I was agreeing with you.