Let’s start with the obvious question, “Why lift the deck?” Good question. Glad you asked.
The main reason has nothing to do with the deck and everything to do with the dogs and the bridges… Well, what used to be the bridges.
Let’s rewind…
When we originally built the approach trestles for the Howe truss bridge, they were built 20″ tall, roughly forty scale feet tall. After we refit the upper loop into the “triple decker” arrangement, we needed a second bridge. We didn’t have a second bridge.
The Howe truss bridge was built over the course of months, with strong attention to detail, which explains why it took months. We don’t have months to build another, let alone time to “refresh” the old one. Not if we want to run trains anyway.
We’d been wanting to try using some metal channels as a stand in for deck plate girder bridge spans. We saved the metal channels from some discarded Levolor® blinds, the tops with the mechanisms removed, conveniently powder coated brown.
Long story short, we quickly cobbled together a couple of crude wooden frames to slide inside the channels and provide a means of securing the two new bridge spans to the set of bridge trestle approaches. Those crude wooden frames were attached to the trestles with screws to keep them in place.
The Problem
The trestles themselves weren’t fastened to the ground in any shape or form, so when the dogs plowed into the bridges, they just repositioned the whole kit and kaboodle! Eventually they managed to rip one of the bridge spans loose, exposing the sharp end of the screw that was torn away from the trestle.
Time to remove them altogether, along with the 10′ span of track that we’ve grown weary of placing back on top of the bridges. We kept telling ourselves if only the bridges were higher, with enough clearance for the dogs to run under them without hitting them, then they may stand a chance of staying where we put them.
Great idea. Only problem is the span that comes off the deck leading up to the bridges is already a 2% grade or better. The bridges would have to be at least 4″ taller, 24″ vs. 20″, but 26″ would be better. If we raised the deck by 4″ as well, it would solve the problem.
The Solution
We’ll stick with “lifting” the deck, since “raising” the deck sounds too much like we’re “razing” the deck. And we’ll have to compromise and go with lifting it 3½”, the thickness of a 4×4, rather than 4″. Regardless of how much we’re lifting it, it must remain level.
As a test, I thought I could lift the deck at one support point at a time while Ann placed a thick shim of wood between it and the deck. I was fooling myself about how heavy the deck is. Even using a chunk of 2×4 as a lever, the most we could place was a chunk of 1×6.
We did manage to get one entire side lifted, but it was all we could do to get those chunks of 1×6 in place, and now the deck is tiling a bit off level. That will have to be good enough for now. It’s going to take a hydraulic jack to lift the deck enough to place those 4x4s. And that will have to wait until the weekend.
Before the jack can be used, we’ll need some means to accommodate its placement. It sure would be nice if it fit beneath the lifting points, but it doesn’t. It’s close, but no cigar. A chunk of 2×2 that needs removed anyway should fit the bill. In most cases just attaching the 2×2 to provide enough of a “ledge” for the tip of the jack to gain purchase is all we need. So one by one each support location is raised and the chunk of 1×6 is replaced by a chunk of 4×4.
The Lift
It’s safe to say that where the deck rests directly atop the concrete post base a chunk of 4×4 is called for and where the deck joist rests in the slot in the base a chunk of 2×6 is required. On the side of the deck closer to the fence the ground is higher than the opposite side which is why part of the deck relies on the slots in the base. Thankfully the depth of the slot in the base is roughly 2″ deep.
There’s a hitch when it comes to lifting the side closest to the fence. The part of the deck that’s supposed to emulate an excavated rock face with a tunnel beneath for the lower loop is nowhere near complete. We’re still working on “what-if” scenarios, trying to figure out what works. The idea is to have a gristmill with a waterwheel fed by a waterfall, eventually, but we’ll save that for another post.
The other “feature” of that part of the deck is that it’s slotted to provide a path for the track to loop back under itself, creating the “triple decker”. That slot is framed on either side by a separate 2×6 joist, each with its own post base. We purposefully made that section of the deck only 6′ wide and angled away from the line of the fence to provide a wedge shape that grows to nearly 2′ wide at the exit of the track slot.
The final shape may not be a wedge exactly since it also needs to provide for a short tunnel for the lower loop to pass through. It’s difficult to find a design that accommodates all the requirements we’re giving it. The point is there are two jacking points, not just the one. That’s where that 2×2 had to be removed since it would be in the way of jacking those points.
The Future
That’s about all we can do for now. The next steps will be designing the trestle approach to the bridges and a means of solidly fastening it to the ground. Certainly hope that 24″ tall is enough to keep those bridges taller than the dogs.