Gradients?

[challenger3802]

I'm just interested to know what is meant by the percentage gradients that are quoted in some of the other threads. (e.g. 2%, 3%, 4%, etc.) We here in Britatin use 1 in 2, 1 in 4, 1in 100, etc. to describe the gradient. 1 in 2 referring to 1 metre up in 2 metres across. How is the percentage worked out?

Thanks
Ian

[Fergmiester]

1 in 2 would equate to 50% grade, which by most standards is a tad too steep. From what I have read the most you'll see is about 4% and even that is considered extreme by all standards, most RR's try to keep their maximum grades to no more than 1 to 1.5%.

I'm sure this will be open to debate.

Fergie

[SSW9389]

Rise over run. In real terms the expression of the number of feet rise per mile of line. 52.8 feet of rise in 5,280 feet is a one percent grade. In HO terms a scale mile is about 60.89 feet. You do the math!

[IRONROOSTER]

The easy way is the number units of rise in 100 units of length. Doesn't matter whether you use inches, cm, etc. Your 1 in 4 becomes 25 in 100 for 25% grade. Many people here use an 8 foot board (96 inches) to test their trains grade climbing ability. You can raise one end of the board 1 inch for 1%, 2 inches for 2%, etc. - it's not exact, but pretty close.
Enjoy
Paul

[tstage]

Ian,

Welcome from the other side of the pond!

The easiest way that I'm able to remember how to convert grade is to use the following formula:

Length of track (in inches) x grade (e.g. 2% = .02) = Amount of rise needed to achieve that

Or, in metric terms for 8' (or 96") of track:

2.44 m (length) x .02 (grade) = 48.8 mm (rise)

Hopefully, that's more helpful than confusing.

Tom

[challenger3802]

Thanks Guys,
That means on my layout I've got gradients of 4% for 4 feet, then 2% round a corner, then a further 4% for 2 feet, running level into a top station.

Or for those of us in imperial land. 1 in 12, followed by 1 in 24, followed by 1 in 12, followed by a level plane.

Ian

[dehusman]

Just divide the two numbers.
1 in 12 = 1/12 = .083 = an 8% grade.
1 in 24 = 1/24 = .042 = a 4% grade.

By American standards you have an incredibly steep grades.

Conventional wisdom says about the steepest you want on a mainline for any distance with longer trains or steam power is 1 in 48 or 1 in 50 or 2% grade.

Dave H.

[challenger3802]

The reason I say 1 in 12 is that for every 12 inches along my trackbed rises 1 inch. And for the loads being drawn up the incline every engine I has wil cope quite well. (The stations only cater for 2 carriages and a loco anyway!)

Ian

[DallasE]

In surveyer and engineering work a1% grade is 1 unit rise per 100 unitsof run. The units can be mm, inches, feet, or what ever you want to use.
96 inches run to 1 inch rise is just over 1%, but near enough to 1% for model work.
A 1.5% grade would be 1 & 1/2 units per 100 units. 2% = 2 per 100, 5% = 5 per 100.

[Anonymous]

QUOTE: Originally posted by challenger3802

The reason I say 1 in 12 is that for every 12 inches along my trackbed rises 1 inch. And for the loads being drawn up the incline every engine I has wil cope quite well. (The stations only cater for 2 carriages and a loco anyway!)

Ian

Ian, an eight percent grade that you are describing is incredibly steep. I think you may be confused because earlier you said that you had a 4% grade then a 2% grade then a 4% grade then a level plane. Immediately after that you said that was equivolent to 1 in 12 then 1 in 24 then 1 in 12, which is completely wrong. Are you using the Woodland Scenics inclines? if you are, each section of 4% and 2% is 24", not 12".
Just my thoughts,
Reed