The Great Wall of San Lorenzo

[MinerFortyNiner]

The following is a brief summary of how I created a cut stone retaining wall for my layout using real stone blocks.



Last winter I started construction of a stone retaining wall after doing much research and contemplation.  I am building an On30 model railroad based on narrow gauge prototypes, notably the Coronado, Detroit Copper and Shannon Arizona railroads located in the Morenci - Clifton mining district in southeastern Arizona.  These famed 20-inch prototypes captured my imagination, and my own Estrella & Sonora Grande railroad is a depiction of a thriving little 30-inch copper mining road carved out of the rugged Sonora Desert.



Here's a photo of the Chase Creek area between Morenci and Clifton...the Coronado Railroad is below, with the Shannon Arizona built later on a higher grade, with the state route precariously weaving its way along the canyon wall.  I love the texture of the scene, and while I don't have space for the creek and road on my shelf layout, I wanted to capture some of the feel of a railroad clinging to the side of a canyon supported by a retaining wall.

Here's an around-the-room tour of the wall, followed by 'how I did it'.



This is San Lorenzo, where the Estrella & Sonora Grande meets the Arroyo Verde & Western.  In the back of the photo is the E&SG climbing towards Estrella, the site of rich copper mines.  This little junction is one of two key focal points on my small track plan.  The retaining wall is one of the first things visitors notice when entering the room, as it runs around half the layout.



Here is an ore train taking some loads down the switchback - let's follow it on its journey down to San Lorenzo yard.  Behind the train, a mine will be be built on a rocky outcropping extending high above the retaining wall.



Here the train passes over a reinforced section of the wall that shifted due to overagressive blasting in the mine.  Typically, mining districts suffer from unstable and shifting terrain around the mines that can plague nearby towns and structures.



This is my initial attempt at simulating the wall sagging outward towards the top, with steel rails driven against mine timbers in an attempt to prevent any more shifting.  It was very simple to build, and I think it adds interest...but has been met with mixed reviews so far.  I welcome feedback!



I am not sure about a prototype here, but I wanted to suggest a very practical approach to address a common problem around the mines.



The wall ends at the end of the tail track for the switchback, which is above the Apache Wells coke plant I completed this summer.  Originally, charcoal kilns were located here and the tailtrack served as a dump track for mesquite wood used to fuel the kilns.



The train backs down the switchback.  Note how I used talus and earth to blend the ends of courses into the terrain.  The layout is ballasted with sanded grout.



Here is a close-up of the texture of the wall itself.  I used about 2,200 travertine stone blocks to build the wall.  More on the construction later...



The porous rock was stained with an alcohol-based stain from Micro-Mark, but virtually any wash would work...it is porous and accepts stain well, I applied repeated applications to simulate staining from minerals leaching out of the mountainside.  I have also successfully drybrushed the face of the stones where a little touch-up was needed, using acrylic paint.



Here is the opposite end of the retaining wall, behind the town of San Lorenzo.  The bridge is an unsettled issue, I originally planned to simulate a concrete bridge spanning a short branch line.  I am debating alternatives, and welcome any advice on what would be suitable.



Here you can see the unstained original stone, as laid in the stepped courses.  I used stone found at Lowe's home improvement stores, and learned tonight when trying to buy another lot that the size has been discontinued.  The stones measure a scale 28" square by 18" deep in 1/48 scale.  That's .690 x .690 x .410 for you engineers out there.  Other sizes are available, and wholesale flooring outlets probably have a variety of stone that could be used in similar sizes.

These blocks came in 18" square sheets, glued to a nylon web backing.  The first chore was pulling them from the backing, it helps to warm the sheets in the sun to make the glue more pliable.  Then I had to soak the blocks in steaming hot water in batches of about 100, and pull the glue residue from the backs.  Then, after air drying the blocks for 24 hours, I glued them directly against the styrofoam subroadbed using Aileen's Tacky Glue.  This glue provides a sturdy bond, but it can be loosened and the glue easily removed from the blocks...allowing me to build a castle someday if I dismantle the layout!



I like how the wall has turned out, and look forward to adding scenery and backdrop above the wall to help blend it in to the landscape.  It fits the dry, thirsty, somewhat forbidding look I wanted to re-create on my layout.  I welcome comments and suggestions!

[gin sot]

Strong work!

Thanks for including the prototype photo-- retaining walls are one of the homogenized model railroad culture shibboleths that have started to annoy me over the past few years, and it's good to see that there is some justifiable reason for them.  I understand that given the spatial limitations of a layout they are sometimes necessary, but I think the trend has gone too far in some quarters.  I almost want to blame Malcolm Furlow, but it isn't his fault, more his acolytes imitating the artist instead of the subject.

Rockwork is one of those things I don't think is generally taken seriously enough in the MRR world; usually the "randomness" is too random in some ways, and not random enough in others.  I hesitate to drag Mike Chambers' name through the mud, but the stone chimney on his influential Woodcutter's Shack diorama is a good example of the effect I'm describing.  You've avoided this by using standardized, almost ashlar-looking blocks-- you can in good conscience say "they meant to do it that way."  Not so the guys who scratch a series of wavy-but-non-intersecting horizontal lines in some plaster, then make vertical hash marks at variable intervals and call it random stonework.

[MinerFortyNiner]

Thanks, I had some trepidation sharing the prototype photo in the context of my model, as they aren't very similar.  My original plan did not include the line on the retaining wall, but I found it visually and operationally uninteresting.  But the space constraints of a 1/48 scale railroad on a 28" shelf require some less than ideal trade-offs.  I couldn't afford the space for a creek, or even for a steep slope.  So, the tyranny of the measuring tape ruled the day.

There's a list in my tired brain of model railroad cliches and contrivances that are unspeakable, with a whole category devoted to poorly done grade separations that seem improbable.  I tried to avoid falling into that set of traps by adopting a solution that met very tight space requirements while providing a unique look...I suppose I could have spent the same amount of time hand-carving random stone, but that seemed a more predictable but less satisfactory approach for what i wanted.  This is the course I took (no pun intended!).  As limestone is a necessary ingredient for flux in smelting, there's almost always a local source that is exploited for this purpose.  It's feasible the mining company could cut blocks at a nearby quarry for a stable roadbed in loose terrain.  It at least seemed a logical approach for an outfit that blasts holes through the earth for fun and profit!  As you can see from the photoshopped background, the color is close to the native rock near Superior, Arizona, which is the general location of my little railroad.

I look forward to completing more scenery above the high line, which will emphasize the vertical element in the scenes and minimize the 'great wall' effect that is evident right now.

[finescalerr]

The very fact that you thought it through so completely is one reason it looks good. Same as with the rest of the layout. -- Russ

[Malachi Constant]

Same here ... part of me sees the long stretch of retaining wall on a model railroad and wants to scream ...

But then I see it all as a work in progress ... and, as you progress, everything seems to be coming together VERY nicely ... so I suspect that your insanity will pay off in the long run! 

Meanwhile, here's a favorite of mine (photo below) ... no one, I mean NO ONE, would believe me if I stuck a bunch of 1/2" scale NBW's into a rock wall on a 1/4" scale layout, but there it is ... right there in the photo ... and dig the wire mesh laid over the terrain in the background ...

Cheers,
Dallas

[Chuck Doan]

Ambitious! That's a lot of work for sure. Regarding the rails used as extra supports; I don't doubt someone might have tried it in the real world.

Neat photo Dallas!

[Ray Dunakin]

The very fact that you thought it through so completely is one reason it looks good.

I agree! IMHO this process of carefully thinking it through is what sets most great layouts apart.

[MinerFortyNiner]

Thank you for all of the comments...it is still a work in progress, but I get a nagging feeling that something isn't quite right with it yet...I will reserve final judgment until I have finished the scenery and backdrop above the wall to help define the setting.

Originally, I was going to build a rock outcropping where the reinforcement is, to break up the wall a bit.  I am still contemplating if i can sneak some rock faces in along the lower edge of the wall in several places to break up the 'dam railroad' effect (as opposed to the damn railroad, as it has been called a time or two!).  This would help suggest the wall is built on the shoulder of a steep slope.

Dallas, interesting photo, I have never seen reinforcing bolts applied directly between rocks...when I have seen them, they passed through a wood or steel beam to help distribute the support over the wall.  I should probably add some NBWs to the wood supports, eh???

[artizen]

Here in Brisbane there is a prototype for the rails holding up a retaining wall at Bowen Hills station. Used to look at it every day on the way to work in the train. However, for the rail to work better on your layout, the wall itself should be on a slight backwards angle (as is shown in the prototype photo). Probably too late to change that now!!!! Retaining walls built to hold back half a mountain generally are built with a slope (canter?) to better cope with the pressure of all that rock trying to push through.

Having said that, I really like the effect you have achieved with the colouring and I think with some weathering and scenics, it will look really good.