Poormans Trestle...

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1.

Just a quick note before I start this tutorial. Since I started putting this information together I have seen some very nice examples of trestle work appearing on Nscale.org pages. From what I've been able to ascertain from the pics and the post this fine work was done with scale strip wood from a hobby shop. I going to present an alternative way of doing things. Ideally, even if you don't want to adopt my material choices and want to use scale lumber, the tutorial will help in other ways like outlining trestle design and construction and just being a general all around guide. I hope so.
Goes without saying that my way is not the only way. Experiment and have fun.
Now on with it...

This project/tutorial came about because of my need for an inexpensive timber trestle. I'm kind of short on hobby funds right now and a quick perusal of the web and the various commercial kits and jigs for building timber trestles convinced me that I either had to figure out a way to build one cheaply on my own or wait. I'm not a very patient person when it comes to waiting on things I want so I set my mind to the task of producing a presentable model out of common readily availabe inexpensive items. That's why I have dubbed this project " A poor man's trestle". A lot of the steps involved in this project might be considered tedious and time consuming by some. If you have more money than time then you might very well want to consider one of the excellent kits that is available . If though, you are like me and have more time than money this is a reasonable and dirt cheap alternative to those kits. The first pic below show the material needed for the trestle. All of these items are commonly available at most any grocery store or discount chain such as Wal-mart. I got the skewers at a grocery store and I don't remember what I paid but it wasn't more than a couple of dollars. I did look at some skewers at Wal-mart that were longer but they were also bigger in diameter and I thought them to be to big. The ones I'm using are about 3/16th's of an inch in diameter. The wooden matches were 77cents and the Elmer's white glue was 97cents. The whole deal comes in at under four dollars.

 


Ok, time to get started. The matches as they come will not work for our needs. Obviously the head of the match has to be cut off. You can use the full thickness of the match for the cap on top of the tresle bent but we need thin flat cross pieces on the rest of the bent.


You will have to split match sticks in half down their length. This actually is not as tedious as it sounds. The work goes pretty quick as long as you keep a sharp blade in your hobby knife. I've just been doing a few here and there and reading N scale.org or watching TV in between. Building the bents goes rather slowly so you can cut enough for one bent or even part of a bent and build some of it and then go back and cut some more. I'm open for suggestions for a better way to get the flat wood pieces for bracing but the matches were the most convenient and easy to find for me. Also, they met the main requirement for this project. They were cheap. I usually give the pieces a quick pass or two over some sandpaper to make them a little more uniform but I'm not real exacting about it as I doubt real trestle timbers are all that uniform.

 

Now it's time to put the jig to work. Cut a full thickness match the proper length for a top cap to the bent. This length is going to be dependent on what you have used for your jig's bent template so I can't give you a specific measurement. Put it in place and then take out five skewers. Try to get ones that are as straight and true as possible. The bag I bought has tons of them in it so you have a lot to pick from. Place a light dot of white glue on the tops of each one and fit them into the jig with the glue end butting up against the top cap. Go sparingly on the glue. You don't want to glue the skewers to your jig. The first pic below shows how things should look. By the way I'm using the full length of the skewers because I'm building a relatively tall trestle. My bracing goes all the way down almost the full length of the skewers for the first few bents that will be in the deepest part of my canyon. Later when I build shorter bents I will still use the full length of the skewers while building the bent. I just won't go as far down with the bracing. After the bent is all built with all bracing in place and the glue is completely dry, I will cut off the excess length of the skewers with my razor saw. This is the best way to do this rather than trying to pre-cut the skewers to length before building the bent. I'll illustrate this later but the point bears making now. Also, it's entirely possible to build a trestle with all the bents the same height. It just depends on what kind of modeled ground you want to cross. Some trestles cross rough rocky territory and have varying bent heights. Others cross areas where , while there is a drop off, the ground is relatively flat all the way across. In the case all the bent heights would be relatively the same. Look online at pics of prototype and model trestles to help you decide which type you'd like to build. Now it's time to start putting the horizontal braces across the legs. Use the split match pieces here and make sure they overhang the outside leg on each side the width of a full match stick. They will hold braces later. I figured out the lengths needed and cut several horizontal braces for each level in advance. Look at the second pic below for an example of where you should be about now. I just put small dots of glue on each leg at the right level and lay the brace in place. I let it dry a few minutes before proceeding to the next one. If you do bump one out of line while placing the next, it's a simple matter to straighten it when using white glue as it stays tacky for quite some time. Soon the legs will get too wide for a single length of match to reach across. We will start piecing them at that point. I'll cover that in the next step.

2.

It's time to get back to the wonderful fun of scratch building a trestle the poor mans way.If you have not seen part one of this project and tutorial it can be found here http://www.nscale.org/forum/showthread.php?t=15937
When I left off I was in the process of finishing off the bents I needed for my trestle.
I have now completed that task and I'm ready to move on.
If you will remember I suggested leaving all the legs of your bents the same length even if you needed different height bents going towards the center from each end of the trestle. If you followed my advice you will have something like what appears in the picture below. Of course you could have aslo built all your bents the same height so the bracing would go all the way down to the same place on each one. In any event I'm now going to show how I go about getting my bents cut to the height I require.

I'm going to take my measurement from my tallest bent. I want to measure down from the lowest horizontal brace to where the skewer "legs" begin to taper into a point. I'm not actually going to cut anything off of these three tallest bents as I will be using a foam base for my "canyon" and intend to push the points down into the foam until the pointed taper dissapears.
On all my other bents I will measure down from the last horizontal brace and use this same measurement that I derived from the tallest bent as a guide where to cut the skewer legs off. In this way all the bents will remain of a proportional relation.
In my case, since I'm using foam, I can actually leave a small bit of extra length on the legs and push them in to level them withe the top of the other bents. Those of you using other base materials will have to be more precise with your cuts.
If any of the above is confusing, don't worry, it will make more sense as we cut the bents and install them into our canyon.

In the next series of pics, I have illustrated each of my steps to cutting the bent legs to height. As I've said before, mine is not the only way but I present it here in hopes that if you don't emulate it exactly that it gives you ideas on how to proceed on your own.
The first pic shows one of the bents that is the next shortest from the center. The measurement taken from the original tall bent in the last step has been applied and marked on the legs in pencil. There is also a bit of the fudge factor built in that I've allowed myself because I will use a foam base for the canyon scenery below the trestle.
The second pic shows where I made a crude jig to hold the bent while cutting it. Any old solid pieces of material that you have lying around will work for this. I cut two flat plates from some leftover masonite I had from my valance and fascia. The purpose of the jig is twofold, the aforementioned ability to hold the bent easily and also to protect the braced portion of the bent that we are still intending to use from damage. As you can see I used a rubber band to hold the flat plates over the bent but I suppose a small modeling sized C-clamp would work just as well. Whatever you use, be sure you don't get things to tight so as not to crush the bent bracing that you worked so hard to cut and glue on!
The third pic is self explanatory, it shows me using a cutoff wheel on my Dremel Moto-Tool to cut the legs. Just a remainder once again, always where safety glasses when operating a tool such as this. For those of us with vision problems, your eyeglasses are not sufficient! You can certainly use other tools to cut the legs. A razor saw would work but I will warn you that the bamboo skewers I used were surprisingly hard and did not cut easily.
The last pic below just shows what the completed bent will look like while still in the jig.

Ok! here I have all my bents cut to height and ready to proceed on to my next steps in the building process. In case you're interested in the details of my trestle, the tallest bents are about 7&1/2 inches high. After the three tall bents in the center of the trestle they get progressively shorter towards the ends. The bents will be spaced an inch apart and as you can see there are nine of them overall. Counting the masonary bridge abutments that will be on each end comes to an 11 inch long trestle. In N-scale the trestle is about 100 feet tall at the deepest part of the canyon and right at 150 feet long. Going to be quite an impressive structure on my layout if I do say so myself.
It's going to take me quite some time to proceed further and document the steps involved in words and pictures so this will be the end of part two with a part three coming in the near future.(hopefully)
Some points I'll briefly metion about part three are that I will be using paint to color the bents. I'm not sure the wood I've used will take any sort of stain and I don't want to gamble the money on even a small can to find out it won't.
If I haven't mentioned it earlier, this trestle will be entirely built and partially sceniked on a base on the workbench and then will be incorporated into the layout.
Well that's it for now, hope you are enjoying this project as much as I enjoy building it and sharing it with you. See you at part three!

As most of you know a trestle is composed of a number of individual leg units known as "bents". There are many different variations of bents in use on different railroads around the United States and probably even more so around the world. My research on the web showed several different styles but probably the most common was the five leg trestle bent. That's what I've decided to go with here. The easiest and most efficient way to get consistent trestle bents is with some type of jig. There are commercial jigs available but they defy the spirit of this project in that they cost too much. It's a pretty simple matter to make your own jig out of a scrap of plywood, some paper and some finishing nails. Mine is shown in the pics below. I got the dimensions and information to draw my trestle bent pattern off the web. I hesitate to say where as they are in the business of selling trestle kits and I'm showing how to build cheap trestles. I don't think I'm about to put a huge dent in their business with this tutorial but all the same I'm not going to mention their name. I suggest you look on the web and you should find the info you need easily enough. I would be glad to scan my template and post it here except for I don't have the facilities to do so. Find what you need a print it out the right size for N -scale. My printer is on the fritz so I drew mine. Once I had the template, I cut a scrap piece of plywood the right size and glued the paper to it. I then cut a top cap piece for the bent from a match and used it and the skewers laid out on the pattern to figure out where to drive my finishing nails to hold the pieces in place. Make sure to use the full thickness of the match for the top cap. A word to the wise, you can go crazy placing nails in the template and I had quite a few in mine at first. The thing to remember though is that you have to be able to lift the bent out of the jig after it is built. I had to remove some of the nails I had put in as you can probably see in the pic. I only used nails to hold the top cap and the skewers for the trestle legs in place. I did not put any to hold the bracing as I figured I could just put glue on it and lay it in place. This works for me. You can put nails to try and guide the bracing if you want. Just remember what I said about too many nails.

 

The next pic below shows the bent with the diagonal bracing starting to be added. You run the diagonal the opposite way as you did on the first side. It's actually the same way since we are turning the bent over. Have I confused you yet?
Just make sure the diagonals on each side form an "X" when looking straight on at the bent. That's the look we 're after. It's the look only a trestle has and what makes them so special and fun to model. These braces are easiest to do by holding them in position and marking the angle cuts with the tip of the knife and then cutting them on your work board. The last pic shows two completed bents. I'm thinking my trestle will have three tall bents in the center and then they will get progressively shorter towards the ends. This is great news for me, less bracing to do.
Just go ahead and leave your bent legs full length and just stop adding bracing farther up for the shorter bents. We will cut the extra leg length off later when we figure out our bent heights.
This will be the end of part one. I hope I've inspired some of you to start a project like this.
Expense is not a hurdle if you use my methods, you just have to be willing to invest some time.
I can't promise when part two will come, it takes time to put these together plus I have to build the projects I'm illustrating as I go. Rest assured it will be coming though.
Meantime get busy building some bents, you will need a good amount even for the shortest of trestles and please feel free to comment or pose any questions you might have. Thanks for reading my tutorial.

 

3.

Time to move on to part three of "the poor mans trestle". The first at second parts can be found here
http://www.nscale.org/forum/showthread.php?t=15937
http://www.nscale.org/forum/showthread.php?t=17027
When I last left you, I had cut all the bents to my desired heights and was ready to make things start actually looking like a trestle. My original thought was to build the foam landscape and then install the bents and then the bracing in between the bents. I'm sure this construction order would still be feasible but after much though I have decided on a slightly different approach.
The first pic below shows the two balsa top stringers that the track will rest upon. They came from an old model plane kit I had that is missing other parts. I found a length of balsa that looked about the right thickness yet it was a little too wide so I split it down the middle to make it two stringers.
Personally speaking, I don't think the dimensions of these two stringers are that critical because they are going to be hidden under track and no one will see them that much.
The next pic shows how I use a piece of Micro Engineering bridge track to determine what the spacing of the stringers should be. I just kind of held it on there and took a quick measurement.
It should be the standard gauge of N -sale track. You can see that the stringers will be barely visible. The last pic shows where I have placed the stringers onto a piece of wood and set the spacing by making a very simple "jig" to hold them in place. It's nothing more than a few nails driven in to board at strategic points to hold the stringers. It's quite like the bent jig made earlier but much much simpler. I apologize for the quality of these pics, the scrap piece of board is kind of ratty looking but it was convenient to grab without having to search my disaster of a work area right now.

Ok, we're going to move on to the first steps of actually making all this stuff look like a trestle.
In the first pic below you can see the ruler laying up against the stringers bering held on my "jig" My stringers are a little over 13 inches long so I cut the distance in about half and made by marks for the center most bent at that point. I then measured outward in each direction marking every inch on the stringers as I went. I got my dimension of one inch between bents on the web.
The stringers are deliberately cut long. the actual trestle length should come in at eleven inches but I made myself some "fudge" room. I can always cut the stringers shorter. Would be much harder to add to them.
The next pic shows a different brand of glue I decided to use at this point. I've heard about this stuff on model plane and model railroad sites. It cost me just under $2.00 so it didn't dent the budget too badly. It seems to be bit more tacky than Elmer's and I thought I needed that while gluing the bents to the stringers. I was afraid that CA would be too quick and not allow me the time I wanted to get things right. A thick viscosity of CA with a delayed setting time might be suitable though.
The final pic in this post shows the first bent glued to the stringers with my modeling square up against it. This is kind of a posed pic. I had to hold things a few minutes before it began to set.
Long way to go but this thing finally shows signs of being something!

 

Here's a couple of pics to indicate what things look like as bents are successively added to the stringers. This particular trestle is to span very steep ravine so the height of the bents grows progressively shorter very quickly. This will vary depending on the look you are trying to achieve.
One thing to point out here is the diagonal braces between a couple of the bents. I was adding these as I went to help stiffen the structure. The ones in these two pictures and in a preview post I had put on the site are actually running the wrong way! There is a right way and wrong way to run this bracing. it has to be run so that the diagonals on the bents themselves will not interfere with it.
Your "X" bracing on the finished trestle will not look right if you don't pay attention. I had to remove these and a few others and redo them. Luckily the glue was still somewhat tacky.

The process of measuring and installing the rest of the bents is pretty straightforward so I didn't continue taking pics after the ones in the last post. Just to summarize, you would just work outward from the center towards each end spacing the bents on whatever centers you have chosen and making sure they are lined up side to side. As we have already covered, depending on your type of terrain, the bents can get progressively shorter from center towards the ends or they could all be one uniform length. This is a choice made when thinking out the design of the trestle and your layout.
The next pic below shows the trestle with all bents installed and the inside diagonal braces glued in place on one side. Once I had enough of the diagonals installed to give some stiffness to the structure I turned it right side up and installed the rest. You should feel the trestle beginning to get quite strong at this point. You should try and make sure it is as straight as possible although when working with these type of budget materials I think that it is impossible to get things completely true. To me this is an acceptable sacrifice form the small cost of the project. You may notice a slight bow or hump along the stringers in this pic. This will be addressed as more bracing is added and I may end up shimming track a little but I don't anticipate this as a problem. It actually isn't as pronounced as it appears.

This next series of pics just basically shows the trestle evolving into a more finished product.
In the first one, inside diagonal bracing has now been installed on both sides of the trestle.
The next pic shows the beginnings of horizontal braces being added at each level along the bents. These braces are made with full sized matchsticks. At the bottom I used the full length of the match by shaving the flammable head of with a razor knife. I might mention that these matches are "strike on box " type and I encountered no problems doing this. I would still advise caution and I wouldn't use "strike anywhere" type matches. As the braces get progressively longer going up the trestle, I've pieced the matches end to end making necessary cuts in the length in order to make the joints meet at a bent leg locations.
The final pic in this series shows a completed side of the trestle with all horizontal bracing in place and the outside diagonals having been added on one side in order to form the familiar "X" pattern we all know and love on this type of bridgework.One quick note to add here, I originally figured the length of this trestle at 11 inches long but I miscalculated. it will actually be 10 inches long. No worries though because the layout roadbed hasn't been cut out yet to accommodate it.

 

After a lot of time consuming work I now have myself a serviceable trestle. It wasn't the easiest thing to do at times but it wasn't that hard either and it was dirt cheap to build. That was the main requirement when I started out along with having a reasonably good looking model in the end. I'm pretty pleased with how things have progressed so far. As I've mentioned a couple of times previously, I was skeptical that the woods I've used would accept stain, especially the bamboo skewers, so I didn't want to invest money into something I wasn't sure would work. If someone has an old can of stain lying around and wants to try it, please report back your results. In my case, what I do have is the acrylic paints that I use for everything. These are available in discount stores craft departments like Wal-mart and in the specialized craft stores. The three colors I used are a light tan that is my base scenery color, a somewhat darker almost reddish brown and black. I use these paints in a cheap Testors airbrush. They have to be thinned to a milk like consistency and believe it or not I use Fantastik spray cleaner to thin them. I picked this up on a model airplane site. Windshield washer fluid and alcohol are also said to work but I haven't tried them. By the way, if you own an airbrush and aren't very adept with it, these cheap paints are a great way to practice. The two pics below just show the aforementioned supplies and the airbrush I use. As I said, this is just a cheap airbrush made out of plastic but it's been my experience that it will accept all the spray nozzles and other accessories that Testors makes for their more expensive airbrushes. I got my compressor at Harbor Freight tools. Nothing fancy here but fine for my needs right now.

The next series of pics shows the trestle as each succesive color of paint was added. First the very light tan was applied, followed by the brown and then the black. I put the light tan on pretty solid but I tried to vary the coverage of the darker brown and the black. A note here from personal experience, it's very easy to overdo the black, be careful. You might also notice from these pics that I've added some brace work at the ends of the trestle and cut the stringers to the proper length. I have a couple of plastic abutments that I dug out of my junk box that I will use on the ends. I understand many people don't have an airbrush but you could brush paint this trestle or use rattle cans. Brush painting it would probably involve painting the individual bents before final assembly. Rattle cans would require a delicate touch with the can far away from the trestle in order not to overdo and get a light coat of paint. Let's hope too that someone can give us experience with how stain works. Lastly on the subject of painting, after the paint is dry you may wish to go back over the sides of the trestle with some fine sandpaper and "distress" the paint a bit. I tried this and liked it, if you don't you could always just retouch the paint.

We are going to use the trestle to measure now and concentrate on building up a foam landscape to accomodate it. I find it much easier to do certain things on the bench and then install them almost complete on the layout rather than trying to do it all on the layout. When I first started working out the height of the various bents, I did it based around stepped elevations of two inch foam. The first pic below shows the foam temporarily stacked with the trestle in place. I had to make a few alterations to make things fit but this is pretty easy to do when using the foam as a base. The next pic just basically shows the very rough landform. The blocks have been glued with foam safe construction adhesive. I might add that I'm down to my last scrap pieces of foam so this may look really ragged but it's not that important as long as we get the trestle legs supported and not hanging in midair. In the next pic I am showing a way to cut and contour foam that is really quick but also really messy. I have a wire brush on my moto tool and use it to carve the foam. I have safety glasses on of course but I also have on a paper mask over my mouth and nose to try and keep from breathing in small foam particles. The stuff gets everywhere and clings due to static. It's nice to have a shop vac handy to clean up after you do this. Either that or just do this outside if possible, although if your situation is like mine, you still have to clean up to keep the family CEO happy!

 

In the next two pics, I'm going to show how I covered the foam with paper towels dipped in thinned joint compound. Normally I would use plaster but I read about a modeler using this method in MR and wanted to try it. As you can see from the first pic, the thinned joint compound looks a lot like plaster. It has a lot longer working time though which is a point in it's favor. You basically just dip squares of paper towel in it just as you would plaster and lay it over whatever scenic form you have chosen. I usually use quarter squares of paper towels with plaster so that's what I did here. The particular modeler I read about in MR uses screen wire as his scenic form. The foam and well supported screen wire are probably best for using thinned joint compound. It takes quite a bit of time to set up and I don't think wadded newspaper or cardboard lattice strips will hold up long enough for it to set and gain rigidity before they would collapse. In this case the fact that the plaster sets fast makes it a better choice for the latter two scenery support methods. I was able to put some joint compound on with a brush, something that's not impossible but very difficult to do with plaster. All in all I was pretty pleased with the joint compound technique but I think I would only use it in small areas and still do the brunt of my large mountains and canyons with plaster. The results of the joint compound work are seen in the next pic.

I had to come up with some type of base for the trestle, I didn't just want to use the foam alone, plus I decided to add some more foam and joint compound to form the back of the ravine. I had the same old ratty schunk of plywood lying around and since it's eventually going to be covered up any way, it became my wooden base. In the first pic, I have laid it on the benchwork betwenn the risers where the trestle willgo and cut it to fit at about the right angle. I gave myself some wiggle room to move it as usual. I just can't ever seem to be super precise when I'm building scenery. The next shot shows the foam landform on the base and the trestle temporarily in place. Everything is roughly lined up with the roadbed and track above it and then marked. The next pic shows the landform attached to the wooden base. as you can see it is at somewhat of an angle to match the track. I still have the option of moving the wood base around should I need to. Also visible is the piece of wood I spliced on to the rear of the base when I decided to go ahead and build the back of the ravine. Everything still fits between the risers on the benchwork.

 

As I said, I decided to go ahead and add the back of the ravine while everything was on the bench and the next series of pics just illustrates that. I just piled up and glued scrap pieces of foam and then carved on them with my moto tool and wire brush. I then covered everything with paper towels dipped in the thin joint compound mixture. Since I was running low on foam, I had some holes that I had to fill. I did this by dipping paper towels in the soupy mix and then wadding them up and stuffing the holes with them. In the next pic you can see the now completed landform, the joint compound is actually still quite wet. It took this forever to set up. I went to bed and work the next day and when I came home there still was an area that wasn't completely set. In the last pic the trestle is temporarily set in place and pushed down into the joint compound and foam..This is the time to make sure everything fits and that you don't have bent legs hanging in mid air. If you do, go back and build up the scenery in that area and test fit again. By the way, I realize that my landform is not the most realistic looking thing in the world. It doesn't have to be right now. The main point here is to get the landscape built in around the trestle bents with as little mess and getting excess scenery material on the trestle as possible. I hate trying to build in any kind of bridge and getting plaster or joint compound or whatever all over it. Once the trestle is installed on the layout and the scenery is built in around it, I can cover it up with moistened newspaper and really blend it in and perfect the landscape around it.

 

 

 

 

 

 

Sidan senast uppdaterad February 4, 2010