A Non-Issue?

Model what looks right to you.  Most layouts trying for big mountainous scenery can't do it well because there just isn't enough horizontal space for the slopes.  Too may times the builder tries to fake it by artificially making things steeper.  It's easier to build smaller landscape features with appropriate scale relative to the trains, as there should be less temptation to overdo it.

Well...you don't worry about it.  Looking the other way, your typical layout set in Appalachia or the Rockies tries to model mountains but ends up falling short.  I've seen a few layouts set in places like you're modeling and "big" scenery both looks right and communicates somewhere in Missouri, or Iowa, or whatever just as it should. 

Consider this:  Close to where I live the UP transcontinental mainline runs through the Wasatch Front in Weber Canyon.  The mountain above the tracks rises to maybe 4000 feet above track level but does so in a mile or more of distance horizontally.  There is literally no way anybody can model that.  Any attempt is going to have to scale that down drastically, and the resulting compromise may look sorta OK but will never truly be an accurate model.  You're talking about a bluff that, in full scale, would be 120 feet tall.  Be glad your prototype presents you with something you can pull off with fewer compromises and build as close to scale as your space allows.  If you have to scale down, the percentage will be far less obvious to a viewer than with the poor guy trying to model Weber Canyon.

I think one of the least productive things we can do is try to adjust our own modeling around some kind of perception the other guy may or may not have.  You know what the scene you want to build looks like.  Make that scene the best it can be and viewers will appreciate it for what it is.

Real "Mountains" are not possible. Ok, maybe in T scale...

8th sub said pretty much what I was thinking as I read your post Ironhand.  The best you can do when trying to model real mountains is show the bottom couple hundred feet of them in most scales and have the slope appear to continue up and out of sight. What you are proposing will actually fit within the constraints of scale and an 8' high real world ceiling. The difference is that the top of the bluff will actually be shown whereas an actual HO mountain would require being built in a grain elevator to fit it in. The big question that I have is where in relation to the bluffs are the rails? If they on top you might have an issue, but if they are along the bottom, probably following a riverbed, then you "have it made in the shade", literally. I am vaguely familiar with the area you are talking about, are the bluffs chalky white limestone? That is something you don't see modeled very often, it might be a trick to get them right.

There are by the way, lots of bluffs in Colorado and the west in general, but folks don't generally hang around those areas when visiting CO and such- they make a beeline straight for the mountains and they fixate on them as soon as they come into sight and don't pay much attention to the "bluffy" areas at the edge of the plains. One rail line in particular comes to mind when I think of a river bottom rail route following bluffs, it is in Wyoming on the way north to Cody from Casper. It's in the Wind River Reservation (I think, going from memory here). Not sure what line that is or even what river, but it is pretty white bluffs for a hundred miles or so. Very cool to see those coal trains weaving through that scenery.

Good luck with your build, it sounds like a good one, no bluffing!

I agree with that

and I think I'll follow it.  I do have the space (layout height and backdrop height) vertically for what I think is 'correct'.  My guesti-mate of 120 scale feet puts me half-way up my backdrop.  I have room for the sky.  It is about 50/50...50%bluff and 50% sky.  There is a side caveat [sorry...Latin...caveat = warning in English], but it's maybe minimal...that being the trees on top of the bluff.  I figure I'll adjust accordingly as things progress.  Bluffs aren't a straight line, but almost separate 'mounds' so there is scenic wiggle room.

I just DON"T want the viewer to say "nice mountains!" when they are not mountains!!

Compression can help

You can create the effect of the bluffs in less than that 16" in HO, I would think. I have seen photos of bluffs along the Mississippi long ago, but some photos would help.

Scale measurement applies to our models, structures and their immediate surroundings...but I've never thought that held importance as you move back from the foreground. As we have seen with effective blending of scenic backdrops with 3-D scenery construction, it takes a bit of art and visual trickery to pull of - but is achievable.

I can share a few photos of the 'bluffs' that were inspired by massive mountains on my On30 layout, but are intended to only depict the closest face of larger landforms beyond. They are severely vertical, by taking less depth than they measure in height.

For their apparently imposing height, they take no more than 18 inches in depth:

Only you know the effect you want to pull off, but I would advise you think about what you can afford in terms of space, and make the most of it. Thinking of building landforms in scale height - even if relatively close to the foreground - will probably not create the balance you want between trains and scenery.

Bluff vs Mountaions

  River bluffs are generally cut down by water action, and many times have horizontal layers of sandstone/limestone.  Mountains are usually tectonic plate 'uplift' and any many times are basalt or granite.  Once can see the 'folds' as the forces of nature pushed the rock.

  My HO river bluffs are about 8-10" high, with trees along the top and the cut strata along the bottom.  here is some work I did at the club:

< a href="http://s862.photobucket.com/user/jrbernier/media/Bridge004.jpg.html" target="_blank"> < img src="http://i862.photobucket.com/albums/ab188/jrbernier/Bridge004.jpg" border="0" alt=" photo Bridge004.jpg"/> < /a>

Bluffs and mountains

I think what you are probably thinking of is a sort of cuesta - a hill that is gently sloping on one side (or has a flattish top) with a cliff on the other and a scree or talus slope beneath it. I made a couple on my previous layout and they look good - far more interesting than up-and-down mountains. They don't have to be very high.

There are very good examples at http://www.australiangeographic.com.au/journal/view-image.htm?index=3&gid=10190    and  http://www.rawnsleypark.com.au/?gclid=CIfrypq3-bYCFWFEpgodP0MA0Q    

Others also at http://www.google.com.au/search?q=bluff+images&hl=en&tbm=isch&tbo=u&source=univ&sa=X&ei=yGiDUfy2DomPiAfHtYHQBA&ved=0CC0QsAQ&biw=1280&bih=847  

and  http://www.google.com.au/search?q=wilpena+pound+images&hl=en&tbm=isch&tbo=u&source=univ&sa=X&ei=FGqDUZ-rOcugiQeKyIDIBA&ved=0CDcQsAQ&biw=1280&bih=847

Cheers

Tony

Size

I would compress the bluffs a little vertically (10-20%).  The key I would think is to have trees or buildings on top of the bluffs the same size as the trees, buildings at the bottom of the bluffs.  That provides a way for people to estimate the size of the bluffs, that they are not a compressed mountain, but are a full sized "cliff".  Other way to make it look right, have a picture of the bluffs hung near the layout entrance.  Point it out to visitors.  That way when they look at the layout it will look "right" since they have something to compare it with.  Once they can make a connection between a real scene and a similar model scene then accepting the rest of the railroad as 'right' becomes easier. 

Here's jrbernier's pic

The area of the lower track, under the bridge, is basically the height I think I need, but with trees up top instead of signals.  I think, as dave1905 said, the key is using tree sizes.  My prototype bluffs are like a wall of trees, with exposed rock faces up high here and there but also down low too.  Some areas are all exposed rock from water to top.  The mention of trees reminds me I'm really not making as tall as I think it is, since there are trees on top.  I do know my prototype bluffs are not nearly as tall as the bluffs north of Dubuque or by La Crosse, btw.

All I think I need do is take some Styrofoam and start experimenting, with trees placed up top and down at track-level to really figure things out.

Bluffs

Enter Mississippi river bluffs in google, many pictures.

                Patrick

Here is a pic

of my proto, but I have to say it was taken when the river was very high, not at all like when I go there.  Usually I have plenty of beach showing.  The river is usually wade-able in most places up to chestdeep, and this pic is not the case.  I didn't take this, it's from the official site of Meramec State Park referring to their canoe trips.

Take the water-level down about a foot and picture a 4-8-2 on the right along the river-bank hauling about 4 passenger cars in the 1950s.

Do-able, and I'm looking forward to the challenge of creating this very image, in fact.  I just really don't want people to look at things and say 'Nice mountains!', hehe.  Looking at this image, if I do it right, the trees should really tell you this is a bluff.  That and the scale of the rock-face maybe.  I'm in Iowa, and anyone looking at my layout (unless I post a pic on MRH) is also going to be from the area and know 'these are bluffs not mountains'... I'd hope.

...how does one do bluffs without making mountains??

Find some photos of the railroad or type of railroad you want to model and copy it in miniature is basically the easiest way. You'll have to compress it but you can capture the essence. The size of layout will determine how much gets built as actual scenery and how much gets represented by photo or painted backdrops and by inference( staging tracks ,interchange tracks, etc) .....DaveBranum

Bluffs Not Mountains

I've modeled both both Missouri river bluffs and Colorado mountains. Among the things which distinguish the modeling are rock structure and vegetation. While Colorado mountains can have both horizontal sedimentary strata and non-stratified granite Missouri will have only sedimentary rocks. Some conifers can be found in Missouri, but broadleaf forests will dominate. Colorado can have flat-topped  mesas as well as mountain peaks. However, in Colorado even a flat-topped peak will have rock exposed to near the top of the formation. Missouri bluffs seldom have rocks exposed near the top of the ridge. Mountains have rocky crests while Midwestern bluffs have forest covered tops. Exceptions may always be found, but so long as you follow these principles visitors to your layout are unlikely to confuse a SE Missouri river bluff with a Colorado peak regardless of how tall your scenery.