thanks for all the great responces.
Dave-the-train:you have deffinatly given me a lot to think about!!!
tim
On my fingers 1foot = 300mm which in N is 150 scale feet, 50 yards or three 50ft boxcars... and you may have twice that length... Which is quite a lot of visual impact... depending a bit on how high the wall is.
To answer the original question the easiest thing to do is to use slices of plywood, Almost anything thicker than 3mm will do... because it is the face of a hill you can support it with wood blocks any way you want inside the hill.
A 3mm ply is an 18" wall and will support itself to a large extent. It will also hold paint and tend to give the paint a matt appearance more easliy than plastic sheet. Also it won't crack as a plaster casting might do.
The advantage of thin ply is that you can curve it along the length pretty easily - and also achieve nice smooth curves, That is if you want a curved wall OR you can make a stepped wall... or a curved wall with steps...or a stepped wall with curves... or angles... or...
The question of the height of the wall isn't resolved... but a wall of anything more than 4 or 5 feet will usually have a batter to it... that is it will lean back into the hill... at least that is the visual effect... the trouble is that the angle can be quite slight and really not show up in pics of the real thing... but if your model has a wall of any significant height and the face does not lean back it will probably give a wrong impression/look weird. The visual effect can be that a vertical face looks like it is leaning outwards. This can mess up the overall image of your model.
Walls aren't often curved vertically but the angles sometimes do change... sometimes from sloping back against the hill for most of the height to vertical for a few feet at the top, bottom or both. Walls can also be stepped. The steps come in all sorts of widths and heights. ...And, yes the steps can have angles... in both the risers and the treads
So why all these issues? All you want is to buy some dollars worth of ready made walls or moulds that you have to mess with... and they will come with pretty much a fixed length and height... and look the same on every layout they are on. You can create your own unique wall for a few cents.
There are a huge number of variations in the final structure appearance of concrete retaining walls.
Apart from the broad differences of shape mentioned there are different ways of making the beasts in the first place. This does matter in the model (even in 2mm) because how the hard concrete got there affects the surface finish and therefore how the light bounces back off it to your eyes.
Ignoring the possiblility of concrete block and slab retaining walls - so as to not be here all week...
Some methods of construction that come to mind...
Pouring the concrete in behind plywood formwork. (Usually where the ground to be retained is pretty stable) The formwork is usually made of 8x4 sheets which can leave an impression in the surface...
Okay in 2mm this will be minute - you could probably pencil the detail of the board edges on very faintly. The pattern of boards might be random or ordered.
Much older concrete may have been poured behind timbers - usually laid flat. The lines between and the grain show up much more... heavier pencil lines in 2mm.
Both boards and planks will have grain running in a specific direction. This won't show as such in 2mm but when it comes to painting the base "concrete colour" you can influence the appearance by making the brush strokes in the appropriate direction(s). Timbers will tend to have horizontal grain but ply boards will usually be vertical or horizontal... and these may be the same for all the boards or some one way and some the other... and these may be in a designed pattern or random.
An 8x4 in N is 8x16mm (1/3 or 2/3 inch) That's 36 or 18 boards along a modelled foot of retaining wall... well... it's a lot easier than doing masonry! The way to cheat is to decide on which way the grain is going for the bulk of it, paint that and then detail in any variations or high lights.
In my view this attention to getting it right is worth it... Why? Because the scenery is always on your layout and on view while the trains roll through. Your trains look so much better against a visually persuasive background.
Okay...
Concrete can be poured between formwork faces and the hill backfilled behind the wall. The face effect is the same but the top of the wall may continue for anything up to 10 feet above the ground... and like a meridian barrier have a distinct shape and signs of the moulding.
I don;t know if it's done in the USA but here we sometimes bore shafts right next to each other in a line, link them, drop in rebar structures and then fill the hole(s) with concrete. The (usually softer) material is then removed from the side that the track (or road) is going to be on. This leaves a retaining wall that looks like a lot of columns side by side with all the marks of the removed/bored earth moulded in the face. In some places this is left as it is. More often some sort of facing is applied. The clever ones are coloured concrete panels that look like masonry.
Quite a lot of places where the a more massive wall is needed the shuttering is made of pressed steel shapes (usually interlinked) and the steel is left in place. This means that until the steel rusts away the structure has a steel face and only a concrete top. A wall like this has lots of interesting shapes and can have lots of detail as the steel degrades.
Then again most concrete wall faces degrade!
Cracks, flakes, crumblings, frost heave, weather damage, plant damage, atmospheric damage, chemical damage... All these and probably more affa=ect the developed appearance of concrete retaining walls. A significant cause of problems, especially in older walls, is often the corrosion of the rebar inside the wall. Apart from flaking and cracks this often produces streaks of rust running from cracks or pinpoints in the concrte's skin.
Which sort of brings me on to the good old question of what colour a concrete retaining wall should be. Almost the only colour a wall should not be is grey... unless it is very new and either delibeartely coloured by additives or quiet unusual in what has gone into the concrete.
The big factor in concrete colour is usually the ballast. use red rock and you will get a reddish wall. use beach material and you will get a speckled pattern...which (even behind formwork) can have a very bumpy surface.
Then there's what colours get added on top of the concrte over the years. A lot of concrete gets stained green(s) if the atmosphere is clean(ish). I've seen this from lurid bright green to dark oine green...and even both together... usually with the bright stuff vertically striped where water runs down constantly.
Which brings me to drains!
If a retaining wall doesn't have drains, gaps or cracks in it then it will act as a dam holding back any rises in the water table in the hill behind it. Like any dam a sufficient weight/pressure of water will break a retaining wall.
For a start this means that you want some sort of provision for drainage. This can be pipes through or protrusing from the wall or just square holes where 4x4s were set in the concrete as it was poured and the drilled out to leave an opening.
[Incidentally you can also get wood plugs set in older walls for things like telegraph wire brackets to be screwed to... the brackets sometimes remain and sometimes even the plug has gone].
What drains down a wall is going to have to go somewhere... this may be a drain along the base of the wall or away from the wall... and in the case of the RR away under the track. Some drains are visible and some are subsurface with only occasional catch pits showing.
One highway underpass near me recently produces its own fountain and waterfall for several months until the maintenance people did some remedial work. There is now a steel pipe out of the wall that bends and goes down into the ground... and probably to the main drains below. There is no apparent reason for this pipe unless you have previously seen the spout of water.
There is also a question of if and if so how a wall is capped...
Hi!
My recently demo't HO layout had all kinds of retaining walls, running about 5 feet in total. Most was from "kitbashed" store bought retaining walls, resembling rock, or cut stone, or wood timbers, or poured concrete. Basically I would cut a piece of masonite to fit the area to be retained, and then would glue in the type of retainer I wanted to use.
In one section, I experimented by making my own wall out of small stones - like the ones used on tarred flat roofs. Again, I cut out the masonite, applied some all purpose glue (you could use caulk or whatever), and lay the stones on top. Once dried, I painted with various shades of grey, and added some thin trails of glue to which green groundcover was applied.
To make a long story short, there are all kinds of retaining walls in use over the last hundred years, and you have plenty of materials to draw from your well stocked LHS.
ENJOY,
Mobilman44
ENJOY !
Living in southeast Texas, formerly modeling the "postwar" Santa Fe and Illinois Central
I've always used Evergreen sheet and strip styrene to build mine.
You have to remember that a retaining wall is going to be site specific... sometimes we rely too much on "off the rack" solutions that force the terrain to conform to a structure. In nature, it always works the other way around. You'll have a more realistic scene if you construct your retaining wall to meet the requirements of the situation.
Lee
Route of the Alpha Jets www.wmrywesternlines.net
This "concrete" retaining wall is made from plastic "For Sale" signs from the hardware store. I cut the plastic into strips and glued with PVC pipe cement. If I were to do it over, I would have made thicker verticle ribs by doubling the verticle pieces with one on top of the other. I sprayed some "speckle" paint on it, and then weathered with acrylic paint. It was inexpensive.
You may see a stone concrete wall in the right of the photo seperating the highest track level from the middle track that is descending to the right.
GARRY
HEARTLAND DIVISION, CB&Q RR
EVERYWHERE LOST; WE HUSTLE OUR CABOOSE FOR YOU
Went to a show last year, but unfortunately missed the scenery clinic, they are usually basic, but very informative. Talked to the fellow that runs them and he showed me a couple of quick, easy tricks, very nice of him.
One of them was for a stone wall/retaining wall. He cut a piece of insulation board (blue or pink) to the shape he wanted, then he took a pen and scribed the stones on the wall. I'd think it would work for concrete too, just don't scribe the stones in, just some fine form lines. Some textured paint would give good texture, but be sure to use one that won't eat the foam or paint the foam with a latex paint first, to protect it.
Good luck,
I have several stone wall molds from Dave Frary, at www.mrscenery.com. Unfortunately, the last time I looked, they were no longer in his catalog. He answers e-mails, though, and he may still have a few available. This is my favorite, which I cast in Hydrocal and then curved around a form before it hardened:
It came out like this, after I cut it down:
Another source is Bragdon Enterprises, www.bragdonent.com. He has numerous rock wall molds available. I've got a rock face from him, and it's a really good mold. This site gives sizes and shows photos, so it's easy to find what you want.
It takes an iron man to play with a toy iron horse.
I have made them of wood and painted them with gray DRYLOK, a latex paint used for sealing concrete block basements. It contains concrete in the paint. Don't try to use it in an airbrush though.
You didn't say how high a wall you needed so I'll give you several recommendations. I'm an HO guy but I believe all of these are available in N as well. Woodland Scenices makes a nice plaster retaining wall system. I believe there are six sections per box. Depending on how tall you want your wall, you can set the rectangular sections vertically or horizontally. If you need a low retaining wall, you might want to consider Walthers modular foundation walls. They could easily be converted to low retaining walls by trimming the top tabs.
Also remember that you can use retaining walls from a different scale to get the size you need. I used the WS N scale retaining walls where I needed a lower wall but not as low as the modular foundation walls. You could just as easily use an HO scale wall if it has the dimensions you need.
This concrete wall in N scale is by Chooch. It's less than a foot long, though.
Modeling the Rio Grande Southern First District circa 1938-1946 in HOn3.
hi
Currently I am in the scenery stages of my 4x8 Nscale layout. In one part there is a steep hill that needs a retaing wall. I thought a concret retaining wall would look nice but I can't seem to kind any concret retaining walls either at LHS or online. The lengh the wall needs to run is about 1-2 feet. I was thinking of making reuseble molds out of styrene and pouring some kind of plaster into the mold. My question is: Has anyone tried this technic of building molds or are there companies that sell concret retaining walls that I have missed.