Bridge selection

The track at this area comes out of the garage staging yard at approximately 43", swings through a door via drop leaf, and then immediately swings parallel to the fenceline to drop down the 4% grade to the main layout (the grade is unavoidable due to other issues). This created a scenario that I would either have to a; create a step up and over at 43" or a duckunder/removable bridge section to access the backyard, etc. Because of the active three young boys in my household that claim part of the backyward as well, I knew the section would have to be removable. 

As I got thinking about this while I was drawing the trackplan, I realized that the area I'm modeling has a few bridges from Woodinville (staging) to Redmond (1st station area) on the prototype.

Bridge #1 just railroad west/north of the MOW shack in Woodinville. I am modeling the MOW shack on my staging yard, but the bridge is going the opposite direction of the layout (east). This bridge according to my engineering charts is a ballast deck, pile trestle, 159' in length

https://goo.gl/maps/ua77omBf15t6CCwF6

Google street view from the bike path along the Sammamish Slough/River.

Bridge #2  is closer to Redmond on 154th Ave NE, and is a reinforced concrete pipe and tile pipe bridge, made up of the following sections 87' of reinforced concrete pipe, 10' of tile pipe and another 88' of reinforced concrete pipe according to the engineering drawings.

Red arrow pointing towards Redmond.

https://goo.gl/maps/Mhy8V3se3hGXsbfA8

Bridge option #3 is a 222' pile trestle with a combination 72' deck girder in the middle. This bridge is just a few hundred feet railroad east of the 154th Ave NE bridge. Like the bridge in Woodinville it crosses the Sammamish Slough. Arrow points towards Redmond. This bridge like it's counterpart in Woodinville also has the bike path that runs underneath. Growing up in Redmond, I used to ride my bike under both these bridges when my Mom and sisters would drag me along for bike rides in the summer. 

https://goo.gl/maps/FQC3MwRBHcUZygM1A

Bridge #4 is the last bridge that would be a possibility, and it's a 170' wide flange beam span. 

https://goo.gl/maps/cwuHfrYRGibSEhjEA

Of all the bridges, I had a couple photos of the Redmond Slough bridge that I had saved over the years from Dave Houston when he shared this image (and others) on Facebook. 

I also had on hand a 2' long deck girder bridge that I had bought from the now defunct Garden Metal Models company. While it's not exactly the same design as the prototype (to my eye the prototype deck girder looks like an old turntable) it would fit the requirements, and be only a few scale feet (12') short of the actual prototype section. This bridge has held up over the years, and I expect it to last many more. Being all metal construction it holds quite a lot of weight (I've walked on it), so it certainly would be heavy enough not to get messed up with repeated removal/installation on the layout. 

More to come on the bridge construction.

Lumber, lumber and more lumber...

After figuring out that I wanted to model the Redmond Slough bridge when I was drawing up the track plan, I realized the need for a massive amount of scale lumber.

This summer when I was in a track building blitz, I fired up my  Byrnes table saw and was cutting massive amounts of ties (bucket below is now in need of refilling). I cut my ties from old cedar fencing (has the tightest grain usually), or new fencing (wider grain). 

While I was making piles of sawdust, I figured I might as well cut some bundles of scale lumber for the bridge as well. I cut the following sizes; 16" x 16", 10" x 16", 8" x 16", 8" x 8", 8" x 6", 9" x 15" and probably some more I can't think of at the moment. I labeled everything and set it aside until I could work on the trestle later. At the same time, I found some 1/2" by 36" dowels at the hardware store to use as the piles. 

As I kept building track and a few #9 turnouts, this section of the layout kept bugging me and I knew that I needed to finish this area sooner than later. 

After a week or so pondering how to start, I started to experiment with construction methods. I had previously built a trestle out of cedar, and it lasted the 5 years that layout was in existence. That bridge was constructed with a 18 gauge pin nails, and treated with a combination of black leather shoe die and 70% ISO. I didn't use dowels on this bridge, but rather used 18" x 18" timbers for the piles. I did learn that the bottom of the bridge rotted out slowly after all the years in the dirt (layout was at ground level). These lessons showed me that I need to make sure the bottom of the bridge could dry out over time but cedar would last quite a while even when cut up into scale lumber. The Redmond Slough bridge, I determined would also use cedar.

Oh great, now you've got me thinking...

Thanks a bunch Craig. I'm about to retire and have had my mind wrapped around my big empty basement. Now you've got me wrapping it around the garden. 

Blessings and curses

Jeff,

Outdoor modeling can be both a blessing and a cure at the same time. First, I'd never ever build a layout that wasn't at least waist high. So that either means a whole lot of fill dirt & retaining walls or an elevated layout. 

On the other hand, it's such a fun scale to scratch build in. The details are big enough to see, you rarely lose parts to the carpet monsters as you can see then when they are dropped...

In all honesty, if I had the space indoors, I'd probably go with P48 or S scale. They are slightly bigger than HO and a lot of opportunities for modeling. But you need a decent sized room. I made to switch to 1/29 almost 20 years ago and I haven't looked back. 

Familiar Territory

Craig,

Thanks for the tour down memory lane.  I've seen those bridges up close and personal many times. In fact, back about 1990, I was building a sectional (HO) layout and tried to carve out space for a wye and went to Woodinville and took photos of those wye bridges, and made pencil sketches, too (all of which are long gone...).  Never did build that wye, but the prototype certainly is cool looking.

BTW, in 1966, while in my senior year at Bellevue High School, I and several friends had discovered surfing, and would spend many weekends out at Ocean Shores or Westport, surfing (wetsuits and tennis shoes almost mandatory).  Anyway, as a publicity stunt, two of us paddled our surfboards from Redmond to Kenmore on the Sammamish Slough.  If memory serves, that was about 5 miles.  Very slow-moving river, as you know.  Sure had some tired arms after that venture.  The Seattle P.I. sent out a reporter and we made the paper.  Those were the days... 

I really enjoy following your progress on this outdoor railroad, given my familiarity with the real thing.

Al Carter, Mount Vernon, WA

Woodinville Wye

Al,

I'd love someday to have the space to properly model Woodinville. The lure of modeling Woodinville may one day draw me back into a smaller scale. Woodinville alone could make a really interesting layout. Add in the locals during the early BN days, plus the MILW detours. Between the 'interchanges' between the various locals at the yard in Woodinville, the thru trains like the MILW (or even during the NP days), and the feed mill in the middle of the wye it would create quite a fun layout. I've always dreamed that it would be fun to get a group of modelers to build a modular setup of the entire Woodinville branch. Each person could take a different town along the branchline. 

If I ever have a large enough space to model Woodinville, I can easily see myself adding it. In this dream world, I'd also have room for Bellevue, the Wilburton Trestle, Maltby.... 

Craig 

Craig

Trestle bent construction

Using the information for some NP and GN drawings on trestle bents, I started to mock up some various heights of the bents based on the prototype photos and some guessing. I came up with a bent height above ground of 15', 20', 25', & 30'. I then added a scale 5' to this in order to attach it to a base and then eventually cover it with my landscaping methods of hardware cloth and landscaping fabric. I guesstimated the height of the triple bents based off the tallest bents. The NP bridge book stated that the bridge was 30' high over the high water mark, and I tried to achieve that as best as possible. In retrospect, I should have made the bottom of the deck girder bridge at 30' above high water vs the top deck of the bridge. 

I mocked up a few small bents to verify my eyeball measurements, and to test out some construction methods. The 1/2" dowels are either popular or oak depending on what my local hardware store had in stock. Oak required predrilling a slightly undersized hole (#64?) in order to prevent the Atlas track nails from bending when I drove them in.

I used Atlas track nails to represent the bolt heads on any visible connection, and used a #18 gauge pin nailer for anything that would be hidden. I also tried out some brass nails I found at the hardware store, but they looked to big for my eye. Brass nail on left, Atlas track nail on the right. 

Part of the mock up process was to determine how to mount the bents to the layout. I ended up with some PVC trim board (it shouldn't warp), and simply drilled a series of 1/2" holes all the way through. This ended up benefiting me in multiple ways later when I made the real bents. I could tap the bents with a rubber mallet to adjust the height, or correct minor errors when assembling the bridge.

I then made a jig out of some scrap styrene to hold the dowels while I added the cross bracing. I later realized this wasn't need if I inserted the dowels in the PVC board first. The PVC boards required a series of 10 degree, and 5 degree off 90 holes to hold the angled bents. Once I had these all drilled out, it was merely a massive effort each evening to assemble the bents. I averaged 2 bents a night until I got them all done.

Here's all the bents for the Woodinville side of the bridge. For some reason, the Woodinville side of the bridge didn't have as many cross braces as the Redmond side. 

Comparison of the two styles.

After I completed all the bents it was time to mock the structure up and see just how big it was going to be. Since I already had existing track, I traced the track outline on some scratch paper, and laid it all out in the garage floor. Because of the bridge being in the middle of a giant S curve, I was worried that I might have to curve some of the bent stringers. In my mockup, I discovered that if I tightened one of the curves on the layout (which was still much larger than my minimum radius), I could make the whole bridge fit without having to curve any portion of it. From abutment to abutment its just shy of 6'. 

Craig

From mock to final install

Once I figured out that the mock up of the right lengths would work, I got cutting more wood. One of the minor changes I made from the prototype plan was using full length stringers vs 28' stringers that span two bents. I figured that it would be structurally more sound using a solid length. These are all pin nailed to the bents, and any bent that need vertical adjusting was tapped into place during this process. I really came to respect my idea of using 1/2" holes to mount the bents. 

The bridge begin to look something like this. Yes there's a bit or a cross level issue in the photo. Don't worry it's been fixed. 

I then added 10' ties, and finally the last section of wood.

Here's the completed bridge waiting for installation on the layout.

To give you HO guys a bit of scale....

Impressive!

It’s quite a structure. I’m really impressed with how you laid out and drilled (especially the angles) the pvc bases. I did a similar thing on my highway bridge, but the holes were all equidistant, straight and perpendicular and that was difficult.

 

And if I understand correctly, you built the bents from the bases up? Are you glueing these at all?

Also, now that I see it take shape I better understand the peculiar variation of bents on either side of the girder.

Drill press

Greg,

 My secret was a drill press with an adjustable table. Unfortunately the use of that tool has resulted in a broken table mount bracket. Now I'm on the hunt for a table mounting bracket for a 1994 Powermatic 1140B model. 

And of course Powermatic makes a benchtop drill press but the column shaft is 3 1/8" while mine is 2 7/8" or 3", ( I can't quite get my calipers all the way around).  If I can find some hobby machinist to make me a sleeve I'd be good.

I started to glue but got lazy and just pin nailed or used the Atlas track nails. It should hold fine as the other bridge was built the same way.

Here's how I built the bents.

Cut a dowel for the center pile 5' over the visual length. 

Nailed that to a 14x14 top piece. 

Cut 2 piles at 5 degrees and 2 at 10 degrees. Cut to length using the center pile as a base measure. I just ran a square across when they all where sitting in the jig holding them in the right place. I pin nailed on the top again.  

Once everything was cut and pin nailed to the 14x14 piece, I tapped them into the PVC base and made sure to drive as evenly as possible. Then I nailed the cross bracing on. 

Then moved onto the next one.

Boy Howdy!

Craig,

 That bridge is absolutely beautiful............I've been in HO forever but what you've got going is very tempting!.........I've got a couple of acres that are just sittin' there...........hhhhhhhmmmmmm. 

bridge #2

Wow, I see prototype pictures from all over the country on this board and then suddenly I see a place I recognize! I lived 3 miles from that bridge #2 for 11 years (2005-2016). Worked at that big company up the hill