Cisco Bridges: a new layout concept

[GaryHinshaw]

Wow, looking really good Scott!  Is it pretty strong? (aside from the middle joint)

I wasn't aware of that Black Canyon stretch; that might be worth seeking out on a future road trip/hike.  Hard to tell what kind of land that is around there, but I see the road that Mike got the shot from.

-gfh

[Scottl]

Thanks Gary, it does seem very strong and I still have quite a bit of cross bracing to complete.  I'm still trying to figure out how to secure the middle joint, but I have a few ideas.  Building this with styrene has been much more forgiving than etched brass.  Working with the bridge walkways and CA glue has been enough to make that clear.

Black Canyon is a pretty remarkable spot on a line with a lot of them.  It is quite close to Spences Bridge on the Thompson River- defintely a good spot to set up for railfanning.  If I manage to negotiate a new room in the backyard (a work in progress...), I might be able to expand my layout concept quite a bit.  White and Black Canyons would be top priorities.  I guy has to have a dream. 

[Scottl]

Just an update on progress.  The bridge is coming along, slowly, but the addition of some brass square tubing on the deck has been good to align everything and with some telescoping tubing, has given me a way to securely connect the two halves of the bridge.  Lots more to do, but things are easing up at work so I hope to get most of this done in April, before fieldwork takes me away.

The bridge is 25" long, and about 7" high.  I'm leaning towards a spring depiction, so the deck will be about 12-14" above the river level.  Thanks for looking.

[packers#1]

so much awesome progressing here...seriously looking forward to more

[Dave Schneider]

Looking great Scott. That is going to be a  very cool scene. Too bad you don't work in the US. No money for fieldwork!

Best wishes, Dave

[Scottl]

Thanks guys, this is the first time I have built anything in the way of a structure.  It is slow going but I'm enjoying the challenge.

Dave, I may be up your way this summer- helping someone start a project on the Dalton Highway.  I would imagine travelling via ANC.

Cheers,
Scott

[Scottl]

A quick update.  I was away much of May and nice weather beckons!  Parts shortages have held me back a bit, but this bridge continues to advance, even if the pictures don't change appreciably.  Here is a picture from a month ago: most of the beams are now faced and the arch beams are getting covered.  I have also been working on the deck ties, which need to be extended by about 200% from the stock length and height of the ME bridge track.  It is slow, finicky work with lots of little parts but I am nearing the point where the primary structure is finished and the deck and lower walkways will be mounted.  While I was away, I prepared artwork for etched beams for the approach trestle, which is another unique CN design and nothing on the market comes close.   My goal now is to finish the main arch bridge by the end of this month, and fine tune the etches and construct them this autumn. 

[Scottl]

After months of efforts, and long periods waiting for supplies, I have mostly finished the main arch of the CN Cisco bridge.  The deck needs railings and the lower walkways need to be fabricated.   I'll probably paint it up soon. 



I tried photos from a variety of angles, here are some that were interesting, if not especially well focused.

[nscalemike]

That looks great!  Will be a great scene I'm sure.  I don't think you would get me walking the catwalk from one side to the other.  Looks like quite a climb on the two ends!!

Mike

[Scottl]

Thanks Mike!

[Scottl]

Four months since an update...  Things have been busy, and my layout and work bench are across the ocean but I'm trying to keep this going. 

The main arch bridge is now mostly done, just some railings and walkways so the next step is the approach bridges.  When I started the project, I bought a Micro Engineering kit to build this, but it has become clear that the kit, while fine in it's own ways, is not a particularly faithful representation of what I am modeling.  So, back the the scratch table...

This time, Central Valley parts won't save me.  There is nothing on the market that will work, so I have decided to try my own metal etches. I've been working on the artwork for the past month or so.  There are a lot of parts, but this file is my version of the two pillars on the approach bridge.  These will face styrene strip sides to build up the beams.  The bridge decks will be made of styrene strips.



A few things to do so far, but will put this together and submit it soon.  Crossing my fingers!

[rsn48]

So Scott, are you going to leave the bridge half painted like the prototype, one part primer only, the other part fully painted.

[Scottl]

That is my plan at this point- the primer orange has grown on me!  I will be back to work on this next month when I am home and hopefully a sheet of etchings is waiting for me.

Right now, I am working on my next etched parts:  walkways and railings.  For the main bridge, I will use Gold Medal Model walkways for the catwalk and the maintenance walkways (6 packages), but I want the top railing to be the distinctive CN type so I'll etch those.  For the walkway along the approach bridges, I'll add the distinctive angle supports as bends and lengthen the walkways substantially to reduce the number of pieces.

What is really stumping me is the details of the concrete-ballasted deck on the approach bridge.  I have only a few pictures from the web and they are not optimal. 

[Scottl]

A HCD?  Maybe, read on.

The reality of building this layout is getting a little clearer and closer, so I am starting to think about how I will actually build it.  I have an existing layout and much of the planned yard will remain, so the changes will focus on the peninsula blob.   This is what I more or less have now:



I'll need to remove this peninsula fully, as the benchwork for the new bridge scene will need to be about 12" lower to provide the necessary relief.  So one way or another, I am building new benchwork for this section.  I'm not very fussed about this and can handle it, but I want to think this through, and particularly, I am also trying to look forward to a possible move in the next few years.  I'd hate to build the bridge scene, only to have to tear it apart for a move.   

It would also be advantageous to be able to build and secure the bridge complex elsewhere.  Maybe I have been looking at too many HCD layouts, but I have started to think that this might be a solution to building this scene.  I've tried to illustrate this below, overlaying on the trackplan.  One scenario would be to build the bridge on a 2' X 4' sheet of plywood, probably 3/4" for stability.  This would be a manageable size that could hold the entire bridge and could be recovered intact if I needed to move in the future.  The cost of this base is trivial- a few dollars pre-cut at a big box.

The alternative would be a larger base in the form of a HCD, either 24" or 30" wide and cut to about 5' long ( I could shift the internal edge board up as I have done before in renovations to maintain integrity).   The advantage of the HCD is a larger space and more of the scene,  almost all of it.  The disadvantage is a higher cost for the HCD (minor, really), and some cutting/fitting time to make it shorter.  The HCD is probably about the same weight as the plywood, but maybe dimensionally more stable.

Either way, the idea would be to simply place the 'module' on the bench work when it is ready, and fill in the scenery afterwards.



The cross-sectional construction diagram is just some thoughts about how to build the levels for track and related scenery.  I will need to sort that out next, and I am leaning towards a foam board structure, strengthened by filling the cavities with spray foam.

Comments and suggestions are welcome. 

[Scottl]

I spent some quality time at the workbench for the first time in four months.  The time was well spent on some projects from the computer, so when I arrived home I had a number of packages in the mail.

With the main arch of the Cisco high bridge mostly completed, I'm now focusing on the approach bridge, which is composted of two viaduct pillars and five steel spans.  This part of the bridge crosses over the CPR mainline and has seen some tough times with derailments over the years, so I am aiming for the post 2011 version with welded steel bridge beams topped with concrete and ballasted track.  Here is a good perspective shot (my apologies, source for this long lost):



Here is a close up, again a lost source:



The unique webbing pattern that CN uses really stands out here, so I decided I needed to fabricate these myself.  With some advice from folks here, I received a sheet of etches from PPD that is perfect.  These turned out very well and will mount to styrene sides.  I was able to easily remove all of the etches and construction is well underway.



I am working on new etches for the suspended walkway and railing on this section of the bridge and hope to submit those for production soon, so I'll just need to fabricate the bridge beams and deck from styrene. 

I must admit, the cross section of a ballasted bridge like this is a bit of a mystery to me and I can't find any photographs to provide some insights.  I assume it must be composed of a steel bearing structure with a concrete floor and side sills to hold the ballast.  I can see the side sills in some photos, but it is not clear if it is made up of pre-fab concrete blocks or a continuous pour of concrete.  Any insights?

One thing I have learned from the main bridge- I'll use a core of brass square tubing and telescoping end pieces to give the deck rigidity, prevent warping, and allow precise alignment during final assembly.

Hopefully I'll have some results to show soon.  Thanks for looking.