Trestle Part 4: Starting to build it in place

It was a very busy weekend between some home repair projects, general yard work, and a trip to IKEA. But I was able to find some time to do a little work on the PE&A. In addition to finishing the retaining wall extension, I did some repair work on the box girder bridges and started building the trestle.

This the the yard junction, site of the retaining wall extension to replace the bricks.

After removing the track and scraping the clean gravel out of the way, I dug out enough soil to slide the first of the two new wall sections into place. Each one is offset just a few degrees.

Here is a reverse angle view showing both of the new sections in place with a brick at the end as an anchor which will be hidden from view.

This shows the finished wall, after back filling, covering with gravel and placing the track back in place. A viewer standing ten feet away now sees a gently curving wall following the curve of the track.  

A new fire lookout tower popped up on the PE&A.

Here's a picture of the lookout tower in progress. This was built from a kit and I finished it a couple weeks ago, but it hadn't made it outside until this weekend.

Another project was to pull out my box girder bridges for cleaning, repair and repainting. A few ribs had come off which needed replaced, and fortunately I still have plenty of styrene on hand. After repairs, I did some touch up painting on both box girders as will as my side girder bridge.

I've been experimenting with what lettering on the box girder bridges might look like. This is just a mock-up using paper letters; once I decide on a size and font I like I'll order some vinyl letters for a permanent solution.

I needed to build one more bridge pier 11 3/4" tall.

Here is the newest bridge pier in place with a board standing in for the missing bridge. You can see underneath the track I've placed markers about 8 1/2 inches apart where each bent will go.

Next I started building the trestle starting from the bridge over the stream bed. You can see here that I've partially buried a brick to support each bent. And I'm using the weight of bricks on top to help hold pieces in place while the glue sets.

Here is a close-up showing placement of the strings on top of the bents. The stringers are all 3/4" high, but the width varies as I'm using leftover wood scraps from another project.

I then added braces on both sides. At this point I began to think I've placed the bents too far apart. I'm also now questioning my plan of staggering the braces instead of lining them up. So I'm going to consider this a first draft; between now and next weekend I will think about what edits I want to make and I will likely rebuild this.

Trestle Part 3: Bridge piers

Progress continues on building the new trestle for the PE&A.I measured the length of the trestle and estimated I would need around 24 bents. So I made nine additional bents this weekend to add to the 15 I put together last weekend. I also spent some time ripping a whole bunch of 1/4" boards that I'll need to assemble the trestle. It is my least favorite task not only because it is so tedious, but because it requires a face mask, eye protection and ear protection. It's noisy and hot and stuffy, so I only want to do it on cool, rainy days. Fortunately that describes what Saturday was like.

I also put together two more panels for the retaining wall which leads up to the low point of the trestle. Depending on how the weather, next weekend I expect to install the retaining walls and the build the south trestle between the retaining wall and the bridge.

Nine new bents.

A big pile of 1/4" boards and a huge cloud of dust.

I'll be extending the stone retaining wall by two feet in order to replace these bricks.

I made the two one-foot wood frames for the retaining wall to accommodate the curve of the track here. Rather than using vertical supports like I did last time, I decided it would be easier if I used horizontal supports made from treated 2x2 pieces I had leftover from another project. The offset of the far left support will make sense during installation.

As I did before, I applied tile to the tops and entire sides of the wood frames. I will treat them this week so they'll be ready to install by the weekend.

And the final thing I did this weekend on the PE&A was build the bridge piers. When a wooden trestle includes a steel girder bridge span, there are typically two or more bents at each end, supporting both the bridge and the stringers that connect it to the next bent. Here are couple of photos of prototypes I found on the internet (example one, example two) that I used to help model my piers. I decided to use three bents for each pier, two of which will support the bridge, and third will be part of the trestle.

First I determined the height for each pier, 9 1/2" for the south pier and 12" for the north pier.

I also had to determine if I needed to offset the tops of the bents. My bridge is 3/4" thick, which by coincidence is exactly the same size as the wood I'm going to use for my stringers. Therefore all three bents would be exactly the same height. 

I marked the height on three bents and then cut off the extra length. I decided to switch to hand tools for this rather than using a table saw.

I then added bottom sills (also known as mud sills) and two more cross beams. These are for the 12" north pier.

Next I bundled them together using small bungee cords, then attached sills and cross boards on the sides.

Here in the north pier in place. You can't tell from this photo but the pier is resting on a brick as a foundation. I plan on placing each bent on a brick foundation rather than letting it rest directly on the soil.

And here is a photo showing the bridge with both piers in place at the end of the day.

Trestle Part 2: Rebuilding the dry stream bed

Work continues on the weekends toward getting the new trestle installed, at least when I'm not too busy with other more pressing yard work. But before I can start construction on the trestle itself there are a number of preparation tasks. The first one was deciding on a bridge design as it will be right in the middle of the trestle.

An overview of the site prior to construction this weekend.

I took a lot of factors into consideration such as material (wood vs. metal), design (truss vs. girder, top deck vs. through deck), and construction complexity (homemade design vs. something manufactured). In the end I decided I wanted something very simple here that doesn't detract from the trestle. So I decided to repurpose my existing side girder bridge, which I will replace with a professionally made Howe truss bridge which will look great in that location. I've placed an order for the new bridge (an early birthday present for myself) and it probably will be here in about four or five weeks—hopefully I'll have my trestle done by that time!

The next step was to clean up the lower half of the dry stream bed. Moles have wrecked havoc in this area over the past few years, and a lot of dirt has become mixed in with the river gravel. I needed to pull everything out of the way, put down a layer of hardware cloth, and then rebuild the stream taking into consideration the locations of the new bridge piers. Laying hardware cloth is something I really wish I would have thought of when I first built the dry stream bed.

A top view of the existing span prior to construction. The 1x4 board underneath the track is 36" long, the same as the side girder bridge that will be going in here. I decided to widen the stream bed here as the support piers will be slightly wider apart than the bricks are in this photo.

I pulled all the large boulders out of the way and then scraped up as much of the rounded gravel as I could. It was really messy as so much dirt had been mixed in, so I built a screen and washed all the gravel before reusing it.

I also widened the area by a few inches on each side, then leveled the surface. This photo shows the site right before the hardware cloth went down.

Due to the widening of the stream bed I now have a small pile of dirt and I'm not yet sure where this is going.

After the hardware cloth went down, I then worked on arranging the boulders. I searched around the yard in order to find a few more to complete both banks. Once I was happy with the layout, I then back filled dirt on the banks, and then returned the washed gravel to the stream bed.

I'm using bricks just temporarily as bridge piers. These will be replaced with trestle bents.

Here's a top view of the side girder bridge in place. I'm probably going to shift it just an inch or so to the right.

The project area at the end of the day. The newly improved stream bed is a wider, much cleaner, and now impervious to mole attack from underneath.

Here's another view of the work area. You can tell from this photo that I still need to clean up that bridge and touch up the paint—another task to add to the backlog.

And one more view from the side. Doesn't that gravel look great?