How to mesure gradients?

Any questions about designing a model railway layout or problems with track work.
Stewart Gethin
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How to mesure gradients?

Postby Stewart Gethin » Sat Jul 10, 2010 6:52 pm

I'm sure i've been told before. but how do I? i've forgot.

i want to know this because apparently my incline is a pretty steep one.

Thanks. Stew.
Please take a look at both my layouts:
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klaatu
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Re: How to mesure gradients?

Postby klaatu » Sat Jul 10, 2010 7:11 pm

Measure the distance along the track, and divide by the height difference over that distance. The result, call it 'X', gives you your '1 in X' gradient. For example, if you gain 2 inches of height over a 50 inch length of track, 50 divided by 2 = 25, so your gradient is 1 in 25.

Steve
Just playing trains - not a "proper modeller"

m8internet
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Re: How to mesure gradients?

Postby m8internet » Sat Jul 10, 2010 8:06 pm

If the horizontal distance is quite short (about two coach lengths) you can normally get with quite a steep gradient
However if the horizontal distance is very long (at least six coach lengths) then you need to ensure the least powerful and heaviest coaches and/or wagons can utilise it
Glasgow Queen Street Model Railway layout : modern image N gauge using DCC

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0121modeller
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Re: How to mesure gradients?

Postby 0121modeller » Sat Jul 10, 2010 10:44 pm

Im wondering about gradients myself , for N gauge , can someone tell me what the approximate length of rising track would be as to clear 2" please ?... I estimate this would be at least 4ft 6", but I cannot be sure.

Cheers :)
Dave.
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bigbob
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Re: How to mesure gradients?

Postby bigbob » Sat Jul 10, 2010 10:57 pm

1:30 would be 5ft so not far off! depends what you`re pulling and what with.
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0121modeller
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Re: How to mesure gradients?

Postby 0121modeller » Sat Jul 10, 2010 11:36 pm

Thanks Bigbob :D I have a bach/farish 47 which will need to pull no more than 6 dapol mk3's, a dapol 2 car dmu, bach/farish cl60 & 6 container wagons, so the trains that'll need to take this route wont be too heavy i dont think.

Cheers,
Dave.
Scratchbuilding 4mm scale JXA scrapwagons ; - viewtopic.php?f=6&t=37620
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Zunnan
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Re: How to mesure gradients?

Postby Zunnan » Sun Jul 11, 2010 9:17 am

You've seen the gradient that I use for a 2" high climb, 10 feet length of run gives me 1:60 which a BachFar class 08 can lift 8 Dapol Mk3 coaches up. The 1:35 gradient on my old N Gauge layout posed no problems for diesels with in excess of 15 coaches, so I don't see increasing that to 1:30 would be much of a problem. However, new DMU models (the class 108, so presumably the 150 too if you ever intend on running either of these) struggled on 1:35 until I added some weight over the power bogie. If at all possible try to allow as much room as possible for your incline, 5' at the very least to give 1:30 but more would be a lot more comfortable, and allow 8-9" in addition for a smooth transition at both ends.

Stewart Gethin
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Re: How to mesure gradients?

Postby Stewart Gethin » Sun Jul 11, 2010 9:39 am

Thanks for the help guys, cleared it up for me.

How can i mesure track if its on a curve? bit of a dumb question really. but i don't know the answer ;)
Please take a look at both my layouts:
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My 5" Gauge layout: viewtopic.php?f=22&t=29058

craw607
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Re: How to mesure gradients?

Postby craw607 » Sun Jul 11, 2010 11:07 am

Hi Stew
When I was building my gradient and came to a curve I used
a tape measure and it will give you a rough length of curve.
John

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Zunnan
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Re: How to mesure gradients?

Postby Zunnan » Sun Jul 11, 2010 12:04 pm

Basic maths :wink:

If you know the radius of the curve then use 2Pi x Rad to give the length of a full circle at that radius then divide the result by how much of the curve there is. 180 degrees (4 double curves) is half the circle so divide by 2, 90 degrees (2 double curves) is quarter so divide by 4 etc. It gets a little more tricky when you're using flex and the curve isn't consistent throughout, for that I use a length of wire tacked to the centre of the inside line (tightest curvature) and then measure the wire. A handy tip when doing inclines on curves by the way, always provide the gradient for the innermost line, that way if you have 1:30 leading into the curve, the inner line will remain at 1:30 but any lines that are outside that curve are shallower than 1:30 because they are longer in length. Otherwise you could have 1:30 on the outer line and subsequent inner lines could get very steep indeed.

locoworks
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Re: How to mesure gradients?

Postby locoworks » Sun Jul 11, 2010 12:58 pm

i could never understand ( and still can't ) why the circumference of a circle is 2Pi x Radius, why isn't it just Pi x diameter??

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Zunnan
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Re: How to mesure gradients?

Postby Zunnan » Sun Jul 11, 2010 1:10 pm

It is, 2Pi x R and Pi x D are one and the same :wink:

But when model railways work off radius its less confusing when you look back over your calcs and see the radius put in rather than a diameter that you are unfamiliar with and doesn't tally up with the numbers in catalogues. It also helps when flitting back and forth working the area of a circle as that uses Pi x R^2. Its all about KISS

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0121modeller
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Re: How to mesure gradients?

Postby 0121modeller » Sun Jul 11, 2010 2:09 pm

That wire against a curved profile of tacks sounds a great idea as to measure the separate one piece 9mm thick plywood for my curved incline :D , Zunnan, your other maths equations are a little too complex for me mate :oops: :wink: .

I've an idea for the possible adaption of normal level board to the inclined section as to enable smooth transition between flat & gradient starting point,... cut a squarish hole 6cm wide x 20cm* in the main 9mm baseboard to fit the starting of 6cm wide inclined section, *= (ideally start off the incline section on a strait route of 20cm) a 10cm x 10cm "strapper" fixed to underside of this recess to support the separate section of gradient (either curved or strait) , I dont use glue as this is too permanent at this early test stage, so I just screw or bolt in place to recess supporting strapper, then, as zunnan says the last 8" of this separarate piece should be on level supports to allow natural transition to the hi-level flat area, the "bend allowance" in the ply should present no problem I reckon.

There is I suppose the other option of jig-sawing out the inclined route from the main baseboard,.. but then you cannot change your mind on this cutout inclined "route" & the in-fill needed for any roadways going underneath this incline would be more difficult to do also as the incline is part of main baseboard top cut & raised.

What I do know & strongly advise is to try to design & build whatever you do with possible future aterarations in mind, That way, if something does'nt go quite to plan on trial & error basis, its then less disruptive to everything else.

Cheers,
Dave
Scratchbuilding 4mm scale JXA scrapwagons ; - viewtopic.php?f=6&t=37620
Scratchbuilt & kit built grappler claw cranes ; - viewtopic.php?f=6&t=36342

locoworks
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Re: How to mesure gradients?

Postby locoworks » Sun Jul 11, 2010 2:41 pm

i use the jigsaw approach to inclines, but i only cut enough of a 'tongue' in the baseboard to get the start of the incline and get the bottom of the tongue above baseboard level. if you do decide you don't like it, you just remove the support and let it spring back into possition and glue it back in place flat again.

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Zunnan
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Re: How to mesure gradients?

Postby Zunnan » Sun Jul 11, 2010 3:39 pm

0121modeller wrote:There is I suppose the other option of jig-sawing out the inclined route from the main baseboard,.. but then you cannot change your mind on this cutout inclined "route" & the in-fill needed for any roadways going underneath this incline would be more difficult to do also as the incline is part of main baseboard top cut & raised.


That is exactly the approach I use :wink: It works out very easy in practice. As locoworks points out, anything you're not happy about at the setting up stage and you just remove the support to the incline and fix the cutout/'tongue' back in its flat position. I go one step further and remove all of the level baseboard around the top and middle of the incline too when its ready to be fixed in place, where the railway isn't level, the ground and surrounding roads are usually even less level. So when I do roads I do them on a separate board and incline them in the same way as the railway, only more severe. The landform is then made by filling in the gaps with loft insulating board and carved down to the road and track level. If you really do your homework at this stage, you can actually make it so that the scenery lifts out and fits back in like a big 3D jigsaw, that way you can even make several different pieces that fit into the same space so you can model differing eras without having to change the track and road layout.


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