Double track 160-to-200-ft Parker-type truss bridge options

[bbussey]

Is there an available option for a double-tracked 160-to-200-foot Parker-type truss bridge?  Similar to the BLMA bridge, but double-tracked.  Similar to the Central Valley Model Works bridge, but in N scale.  I'm hoping that it won't have to be scratchbuilt and I don't want to pay an exorbitant amount, although admittedly I would have considered the BLMA bridge if it was double-tracked.

[Chris333]

You just have to talk nice to the magic pixel generator and it will spit one out.

[bbussey]

I hope I won’t have to scratchbuild one. That’s going to be a major impediment for me in September/October, based on my current rate of progress.

I might be forced to pick up one of the CVMW bridge kits and reverse-engineer it. 

Or, it might be possible to incorporate components from the Atlas code-55 truss bridge to save on time and expense.

[bbussey]

Ugh. If I can’t put a commercial bridge in place, I might as well try to represent the actual structure, which is the original Shaw's Cove Bridge in New London. Amtrak replaced the bridge decades ago but there should be a source for specs/drawings on file somewhere, either at the Library of Congress or at the NHRR archives at UConn.

[garethashenden]

Walthers have a Pratt truss kit, but it has a curved top chord which is the distinguishing feature of a Parker truss. But it’s single track. Maybe you can stretch it?

Or there’s this:
https://www.walthers.com/curved-chord-through-truss-bridge-w-2-piers-fine-track-assembled-double-track-red-22-quot-56cm

[randgust]

They are out of stock on Plaza Japan and Walthers but I found a couple on Ebay.

This is one of those cases where you may use that as a stand-in until you are able to scratchbuild the exact bridge you really want, if the span dimensions are close enough.

[samusi01]

HAER may have plans offline... a brief look netted only a series of images, which I should imagine you already have:

http://www.loc.gov/pictures/search/?q=Photograph:%20ct0394&fi=number&op=PHRASE&va=exact&co%20=hh&st=gallery&sg%20=%20true

At least the older span would be easier to find a substitute for, being less visually distinctive than the present one.

[bbussey]

Walthers have a Pratt truss kit, but it has a curved top chord which is the distinguishing feature of a Parker truss. But it’s single track. Maybe you can stretch it?

Or there’s this:
https://www.walthers.com/curved-chord-through-truss-bridge-w-2-piers-fine-track-assembled-double-track-red-22-quot-56cm

That's the Tomy bridge.  Too modern-looking and too foreign-looking unfortunately.

I'm going to focus on the flat top truss, which is what the original Shaw bridge was.  I was hoping to use a good-looking commercial offshoot because real-estate is tight to model a cove as opposed to a waterway.  But since I have to fabricate something, I'm going to base it on the prototype and model the swing mechanism  under the span as well.

HAER may have plans offline... a brief look netted only a series of images, which I should imagine you already have:
http://www.loc.gov/pictures/search/?q=Photograph:%20ct0394&fi=number&op=PHRASE&va=exact&co%20=hh&st=gallery&sg%20=%20true
At least the older span would be easier to find a substitute for, being less visually distinctive than the present one.

True, it's easier to fabricate from models that exist already.  Or rather, it becomes primarily a kitbashing project as opposed to a scratchbuilding project.  I have to procure dimensions, then I'll know what I'm dealing with.

[randgust]

That sort of reminds me of what I had to do for the Hickory Bridge - I started with the single-track Central Valley truss bridge, and backdated it with rods and pins and completely replaced the deck as it was a dual rail-road toll bridge.

http://www.randgust.com/WHDP017.JPG

I liked the Central Valley parts - and you can buy some separately as well - but the plastic was surprisingly brittle and there was a lot of flash.

[sirenwerks]

Walthers have a Pratt truss kit, but it has a curved top chord which is the distinguishing feature of a Parker truss. But it’s single track. Maybe you can stretch it?

Or there’s this:
https://www.walthers.com/curved-chord-through-truss-bridge-w-2-piers-fine-track-assembled-double-track-red-22-quot-56cm

Oooh, that's got Pac NW highway bridge written all over it...

[bbussey]

That sort of reminds me of what I had to do for the Hickory Bridge - I started with the single-track Central Valley truss bridge, and backdated it with rods and pins and completely replaced the deck as it was a dual rail-road toll bridge.

http://www.randgust.com/WHDP017.JPG

I liked the Central Valley parts - and you can buy some separately as well - but the plastic was surprisingly brittle and there was a lot of flash.

If they sell the parts separately, I would be willing to go that route.  I might even be feasible to start with full kits.  Their N scale models might be a good starting point in any event, not that I'm focusing on the flat-top prototype.  That also would afford the option of 3D-printing any necessary prototype-specific details.

[Wutter]

Ugh. If I can’t put a commercial bridge in place, I might as well try to represent the actual structure, which is the original Shaw's Cove Bridge in New London. Amtrak replaced the bridge decades ago but there should be a source for specs/drawings on file somewhere, either at the Library of Congress or at the NHRR archives at UConn.

If you're trying to represent the original Shaw's Cove Bridge, isn't the New Haven era bridge a straight Pratt truss, and not a Parker truss?
1913-1984 Original:

1984 replacement:
https://www.wikiwand.com/en/Shaw%27s_Cove_Railroad_Bridge
https://www.loc.gov/resource/hhh.ct0394.photos?st=gallery

[Chris333]

Could you start with this and do a little kitbashing
https://www.walthers.com/double-track-truss-bridge-kit-10-x-2-3-4-x-2-3-4-quot-25-x-6-8-x-6-8cm

[thomasjmdavis]

In my box of stuff I haven't gotten around to in the last 30 years, I still have one of those Plastruct kits.  The instructions that come with it build into a 123' warren truss (I think) single track bridge, but since it is, essentially, a bag of styrene sheets and shapes, and scratchbuilding instructions, you can build just about anything you want that can be made with the parts.  However, for the bridge in question....

The biggest problem I see, if trying to build the original bridge in Wutter's photo, is to fabricate the columns that are open with diagonal bracing (GMM does/did make diagonal bracing, but still needs to be assembled with other materials). Most N scale bridges just use H-columns or something similar.  Accurate enough for a more modern bridge, but not the late 19th/early 20th century bridges like the one in the photo.

I spent a lot of time trying to find diagonal braced columns- I need about a scale mile of columns with bracing like those- for my trainshed project- the only source I can find are Walther's water towers- and I can't see buying enough water towers to yield the columns I need.

[wazzou]

However, for the bridge in question....
The biggest problem I see, if trying to build the original bridge in Wutter's photo, is to fabricate the columns that are open with diagonal bracing (GMM does/did make diagonal bracing, but still needs to be assembled with other materials). Most N scale bridges just use H-columns or something similar.  Accurate enough for a more modern bridge, but not the late 19th/early 20th century bridges like the one in the photo.

I spent a lot of time trying to find diagonal braced columns- I need about a scale mile of columns with bracing like those- for my trainshed project- the only source I can find are Walther's water towers- and I can't see buying enough water towers to yield the columns I need.

You get this with the Central Valley Bridge.