Spring 2023 Infrastructure Improvements

Big Enhancement To New Upper Loop

The Battle Continues

It goes without saying there are even more stringers in need of replacement! It’s been difficult to keep up with only weekends to effect repairs. This says nothing about new additions or improvements so far. More stringers. Ugh. It should be obvious from that statement we have yet to get to any casting whatsoever. In fact, we’re actually moving in reverse, removing track the dogs have knocked loose from the stringers, just hanging off the sides.

We had to put up “blockades” on either side of the shed to keep Kai from bounding on, and potentially breaking through, the fence. Unfortunately, she’s pounded those 10′ diameter curved stringers to pieces, literally. It’s the only place I’ve yet to remove the track where it’s hanging. In fact, there are at least two more stringers that need replaced to make that deadline and another section in need of repair as well.

I’ve had a set of “plastic” 2x4s standing in the garage for years now, with the intention of using this material to construct stringers to (hopefully) last longer than any made from wood. I call them plastic, but they’re actually a composite of wood and plastic. I ripped the three I had into slats last weekend and got the 10′ diameter curved stringer template out of mothballs in the shed.

What’s Left Of The Curved Stringers
New 10′ Diameter Curved Stringers

 

 

 

 

 

 

 

I have to say I certainly hope they last longer than wood because they are especially more difficult to rip into slats than their wood counterparts! They don’t really make much “sawdust”. Rather, they create many small shavings that want to clump together, clogging the vacuum in the process. Not sure what make them want to cling to each other, but what a mess! Don’t think we’ll be using this stuff again. The PVC siding I used to replace the bottom course of shiplap didn’t make this kind of mess, so I was surprised.

Our New Deck

Like last year at this time, we’re shooting for running trains Memorial Day weekend. There’s still quite a bit to do, and the stringers aren’t the only repairs that are need. The constant pounding by the pups has once again destroyed the two curved legs of the wye. One rail will need bent back to the proper radius and made flat with the rest of the track. While I’m reluctant to just put them back in place, for now it’s the only way we’ll be running trains by the weekend, even with Friday and Monday off work.

It’s a bit disheartening seeing a stack of track sitting on a rocking chair on the patio and all those stringers we replaced with no track attached. It’s been months since we’ve been able to run trains. But all this doom and gloom is balanced by our deck project. The deck is coming along nicely and nearing completion. The deck is actually part of the road bed for the new upper loop! It’s a cozy place to be, surrounded by trains as they pass. At least that much is nearly complete.

Our Deck Is Coming Along Nicely

We still need to work out how to craft the short tunnel section where the lower loop passes under the middle section and meets the deck. For now it’s just makeshift stacks of concrete blocks and decking “cut offs”. We decided not to extend the deck all the way to the planters along the fence to leave ample room for the dogs to run and chase each other. Kai can really fly when she’s chasing those pesky squirrels!

Along those lines, we’ll need to figure out some other means to blockade Kai from behind the shed and accommodate running trains. We’re thinking some sort of tunnel entrance on one end and perhaps a giant industrial building facade with through passage beneath. I don’t recall what prototypical building this represents, but I do remember seeing one like this somewhere. At this point, anything will looks better than the chunk of plywood and section of fence we’re currently using, neither of which will allow trains to pass.

Other Improvements

As part of the deck improvement, we’ve added an underground power feed and a number of irrigation lines out to the deck. It’s a start anyway. The idea is to get the trenching done and out of the way before we continue to add more dirt to the planters that back up against the deck, to avoid having to move it more than once. It took several weekends to accomplish, starting with the first ten feet from the house to the edge of the lower loop.

Actually, it passes just beyond the lower loop, but that first ten feet is where the dogs like to chase each other around. We want to make sure it’s backfilled so when the pups play they won’t get hurt. The first four feet is basically just pavers out from the house, so the most difficult part was moving the dirt elsewhere rather than piling it on top of the pavers. From there, the next five feet is covered by artificial turf that we pulled back out of the way, and now a tripping hazard.

Banana Shovel Nearing The 10′ Mark

Even using the “banana” shovel, a long and narrow shovel meant for trenching, it takes into the afternoon to get down to 18″ deep for the conduit. Once the conduit and elbows are glued up and placed into the trench, it’s backfilled and compacted to about 6″ deep for the irrigation lines. Three of them, to be exact, basically ¾” PVC to support multiple irrigation zones. Those are backfilled as well to where the turf can be laid back down to cover the path.

Not sure what happened with the stretch of conduit at the house up to the outdoor in use box. It measured 44″, then fell short by 4″! You’ve heard “Measure twice, cut once”? Try “Measure thrice, cut twice”… It’s not that big an issue, just means it will need a splice before landing it in the box is all. For the irrigation lines, they stop short of going under the deck, mainly because some of the decking will need removed to gain access beneath in order to finish trenching.

Future Enhancements

Obviously we need to finish up the “utilities” to and around the deck. The conduit and irrigation lines now extend to roughly 20′ from the house, but remain unterminated. Unfinished. Most of those improvements will be covered in the deck series and not here. Eventually the conduit will feed power for lighting and other features on the deck. The irrigation will split out in “T” fashion, one leg heading to the planters along the fence, another toward the other planters along the other fence by the garage, and the third will feed the deck area and terraced planters themselves.

The pond was definitely an enjoyable feature, even with its drawbacks. The problem was no planning or thought was given to an overall sustainable system, not even basic filtration, and that became its undoing. Having to constantly drain, clean, and fill the pond on top of constantly toweling off the dogs was just too much like work.

At some point the idea is to add a waterfall at the end of the deck, and perhaps more of a “water feature” to go along with it. Another idea is to place a water wheel powered grist mill near the waterfall, fed by the higher head upstream, complete with rail siding to serve it. These features would take the place of a railing, providing a “natural” transition back to the railroad near the bridges. We’ll need to get closer to completion on the deck before that.

Our Howe Truss Bridge Showing Its Age

Speaking of bridges, plural, we’ll need to rework the existing scratch built Howe truss bridge into two. It may be easier to just scratch build two new bridges and save the old one for later. Still back and forth with whether to make the new bridges more modern steel versions or stick with the old timber style. We’ll need at least one more bridge for the section of triple decker that passes over the ground level lower loop track.

Before all that, castings. We’ve said it before, and we’ll say it again, castings are on the way. Once the 3D printer is tuned up and back online, we can print the molds we’ll need to cast the cut stone arches, and hopefully “restore” the downtown marketplace. And by restore, we mean rebuild. There’s more design work to be done around downtown before we can get to that, like how to route “utilities” under the streets, and how to pour the concrete for the streets and building foundations.

For now we’ve just removed what was left of the crumbling backer board that once provided a convincing illusion of main street and covered it with artificial turf. Jasper, a 12 week old puppy and the latest addition to our team, has a way of finding anything and everything we don’t want him getting into. It’s a full time job!

Once we collected up the pieces of backer board to keep him from chewing on them, he found the little stones in the gravel beneath that provided the road base and proceeded to chew on them! After covering the gravel with the turf, you guessed it, he started chewing on the turf and dragging it up by the corners!

 

 

 

 

 

 

 

 

Building A Howe Truss Bridge

Building Our First Bridge

Our garden railroad is progressing, but we need a bridge. As with the trestle bents, this post is a foreshortened version of all the research and planning involved. I’m an incurable rivet counter when it comes to details and modelling, a hold over from my HO scale days, so it is difficult for me to accept anything less than prototypical.

The approach I settled on is, shall we say, less than prototypical. But it does allow for “quick” assembly, combined with a modular approach. And again, like the trestle bents, it requires a jig. Beyond that, it also requires additional brass hardware… Threaded rod, nuts, and washers for examples. I chose to use #2-56, but #1-72 would be closer to scale.

The modular approach is an adaptation of a commercially available system for building a Howe truss bridge. The modular concept to based on “opposed overlapping” end pieces, coupled together by multiple standard overlapping sections. A prototypical Howe truss bridge is composed of massive compression members, and comparatively “puny” tension members where iron rods assume the tensile forces.

Sounds like too much engineering mumbo jumbo? The quick and dirty version is wood doesn’t take kindly to stretching, and metal doesn’t like to be pushed, even in the form of a spring. The design of a Howe truss accounts for this and it’s appearance. Another feature of its appearance is the reason why my rivet counting background makes this difficult for me.

The prototype uses a metal casting to bring all those components together, a component I cannot replicate with the modular approach I adopted. Someday perhaps, but not now. The prototype does not use the massive 12×12 beams, both above and below, to contain the trusses and terminate the tension rods. But I’m getting ahead of myself. We don’t even have trusses yet!

Building A Truss Jig

After a number of false starts, I finally came up with a final design and a jig to hold thing together for assembly, which starts with placing upper and lower members. Then the first course of diagonal compression members are placed over those.

Another set of upper and lower members is placed over those, but these are a “cell” shorter than the previous. Then another course of diagonal members, this time in the tension direction. One last layer of upper and lower members, yet again a “cell” shorter.

 

Hopefully the pictures are worth thousands of words, but perhaps I should start with how I made the jig. I learned from my experience with the trestle bent jig and started with a chunk of ¾” plywood. After carefully calculating the placement for the upper and lower truss members, I proceed to cut ½” wide slots for both members, 3⁄8″ deep, using the router.

Those upper and lower members are only ¼” thick, but the jig must be recessed enough to allow for the diagonal members to be placed over them, which accounts for the 3⁄8″ depth. Again using the router, I cut slots for the first course of diagonal members, this time only 1⁄8″ deep. I’ve never really had much success with using the router, even with a guide, so I’m a bit nervous.

Those with a keen eye will notice that I missed by half an inch on the lower slot and had to cut another next to it in the correct position. I must have miscalculated, but thankfully was able to correct for it without having to start all over again.

Building A Truss

By building two of the end assemblies, one can be flipped over and placed on top the first such that the diagonals overlap and fill in where the other is missing them. A truss constructed in this manner will be rather short and somewhat useless, but it demonstrates the approach. Another picture is in order. The horizontal members are roughly nine inches apart. Where the diagonals meet them are about four inches apart. The minimum truss length is about two feet.

Modular Truss
Modular Truss Construction

A truss of arbitrary length can be constructed by first starting with a pair of end sections. Any number of intermediate sections can then be inserted between the two end sections, using the same offset technique for placement of the diagonal members, except the length of all the horizontal members of the intermediate section are all identical. The intermediate sections don’t necessarily all have to be the same length

This is the modular approach I borrowed in hopes of building the bridge trusses a section at a time, then later assembling them all together into one long truss, four feet long. The jig allows me to build intermediate sections up to two feet in length. Combined with the two end sections yields the desired four foot span.

Each and every joint requires cutting a piece of the threaded rod, and that requires chasing the threads, mangled by cutting. The rods come in three foot lengths. The joints need a chunk less than an inch long. Before cutting, nuts are threaded on the rod to chase the threads after cutting on their way back off, but this proves difficult and ineffective.

While using the nuts is good enough for proof of concept, the rivet counter in me prevails. A good set of threading dies make the task much easier. The correct sized machine bolt would be perfect, but the only items available in these small sizes are machine screws.

We’ll stick with the more prototypical nuts, although hex nuts aren’t strictly prototypical either. Square nuts and square headed bolts would have been used on the prototype. Also not strictly prototypical is the way the horizontal beams are joined, but short of stamping or casting joining plates that the prototype employs, this will be close enough.

The most frustrating part of assembling a truss is having to partially disassemble the modules just to join them together and reassemble. It’s hard enough for my fat fingers to fumble with threaded these tiny nuts on the rods once, but having to do it twice or more is trying my patience.

Perseverance prevails and I finally have two fully assembled trusses. Now to join them together into the final bridge span.

Building A Bridge

The two trusses are held together by pairs of scale 12x12s and tension rods. The scale 12x12s are cut to extend beyond the sides of the trusses. Holes for the threaded rods are drilled in the ends. Threaded rods extend through the pair of 12x12s, above and below the trusses, secured by nuts and washers on the tension rods.

Sounds simple enough, but no amount of hands seems enough to hold everything together while tightening the nuts on the rods. A different approach is called for. By preassembling the pairs and rods, sliding them over the ends of the trusses, then tightening to hold everything snug works much better.

 

Assembly continues by just snugging the rods at first, then tightening them until they can be “plucked”, like tuning guitar strings. More like bass strings as thick as the rods are, but they still make their own music of sorts.

As the rods are tightened, the structure becomes more rigid, but wants to twist the tighter they get. It appears the trusses are deforming under the force. Attempting to twist things back in shape causes the trusses to deform further.

We have a bridge! Good enough for now, but there shortcomings that will need work.

Items To Address

The first issue encountered is accurate and repeatable placement of the holes for assembling the truss members. A few modifications to the jig will allow the use of my dremel drill press and a means to accurately index the holes. It should help speed up assembly, but assembly will remain clumsy and difficult using the modular approach.

Another disadvantage is joining the horizontal members “together” where the diagonal members join. A less than rigid truss assembly produced. Even though the joints are staggered, the forces applied by the diagonal members tend to force the horizontal members apart, much weaker in comparison to a single member.

Slop inherent in the modular truss approach could be overcome using a number of different approaches.