Building a Bent Jig For A Wood Trestle Bridge

By Larry Dick

OK, can someone name the one thing that is constant in all railroads from Z scale running around a hat to real life scale running around the country? What’s the single most common feature on any railroad that stands up, beats its chest, and screams trains? ...That’s right Bucko, that something is a wooden trestle bridge. If you own, or are planning to build a model railroad, chances are you have incorporated one or more wooden trestle bridges somewhere on your layout.

A trestle bridge is a statement to other model railroaders attesting that you are serious about your trains. There is a higher probability of Utah voting Democratic than trying to find a modeler who does not have at least one trestle bridge on his or her railroad.

To be sure, the lure and grandeur of a wooden trestle bridge is especially pronounced on large scale railroads. Anyone who has visited a garden railroad and has viewed this type of bridge sweeping around a mountain curve or spanning a river valley had to be immediately impressed with its impact. I remember seeing my first garden railroad and was taken aback with the stunning appearance of its trestle bridge. I wanted to buy and take home a five year supply right there.

Not wanting to be shunned by my fellow Pacific Crossing club members, I knew that I must incorporate a wooden trestle bridge or three in my ‘now under construction’ garden railroad. At first glance, all of the cris-crossing pieces of lumber seemed somewhat daunting, and it became apparent that in order to achieve some uniformity, it would be necessary to build a jig. What follows is a step by step method used to construct my trestle bent jig. Before I begin, I would like to thank Don Boulware of our club for letting me photograph his superb bridges and for letting me study his homemade jig. I don’t think that I could have succeeded without his generous help.

Step 1:

I decided to construct the bridge from cedar fence slats. They are readily available from any home improvement store such as Lowes or Home Depot and with proper treating, would probably last a long time. I choose slats that were slightly less than 5/8" thick and six feet high. After determining the height and length of my trestle, I began ripping the cedar slats on my table saw in 5/8" wide by 14 inch lengths. My bents would consist of five vertical posts with top, middle and lower horizontal beams. Cross members would be added later.

Step 2:

I used a hard, thin piece of plywood as a base for the jig, and drew the outline of the trestle bents on this plywood in pencil. I also glued a piece of wood at the bottom of the jig to line up the vertical joists.

Step 3:

I knew that the top horizontal brace would sit on the vertical posts and the bottom brace would be located at the foot of the verticals. However, I needed to locate the middle horizontal cross beam. Once I determined the location of the middle brace, I glued three wood stops to line up the brace across the bent (see figure 1). Figure 2 shows a horizontal brace resting on the three wooden stops.

Step 4:

After the middle horizontal stops were in place, I simply started to glue the wood stops for the five vertical bent posts in place. This was easily accomplished by following the pencil lines drawn in Step 2. Four stops were used per vertical post. Two stops were glued above the middle horizontal brace line, and two stops were glued below the line. Figure 3 shows the middle vertical post fit between the four wood stops.

Step 5:

The remaining vertical wooden stops were glued in place for the other four vertical supports (see figures 4 and 5). The center lines of all of the vertical joists were drawn in blue for ease of placement. Figure 6 shows all five vertical bent posts in the completed jig. The horizontal brace member will be glued and nailed to the vertical posts.

Step 6:

Once the horizontal cross member is in place, the top and bottom vertical posts will be cut level to accept the top and bottom horizontal beams.

That’s about it. Stay tuned for part two of this article where cedar cross strips will be glued and nailed to give more strength to the basic bents. If you have any questions regarding construction of the jig, please feel free to contact Pacific Crossings Model Railroad Club.