Baton Rouge Southern - Chapter 2

[wazzou]

Bad photos loosely translated:


Thanks, and have a nice day!

Lee

Being familiar, as I'm in the business of providing these types of timbers.  The stringers more often than not are 8x16, 8x17 or even 9x17.  Generally there are three under each rail which looks to be the case in the proto photo Lee referenced.  Pile caps, supporting the stringers are most often 14x14, 14x16 or pairs of 8x14 bolted together.

[Philip H]

Yeesh, this slipped to the second page of Layout Engineering.  Gotta post more often I guess.

Borrowing Lee's excellent drawings, I ponder this:



Of the cross members we see in real life are bolted to the trestle tops, who do so many manufacturers of pre-made trestles just glue the bents to the timber top?  The answer is obviously speed of assembly.  but that's not my style.

So anyone got any side on shots of the timber under the stringers but at the top of the pilings?  Does the RR just shove in a spacer block while they through bolt the centers to the pilings?

[wazzou]

PM me with your e-mail and I'll get you what you need.

[Philip H]

Thanks to Bryan's excellent documentation, I have a few new angles to approach this with, so to speak.  Film tonight at some point.

[Philip H]

So first every bridge needs a good deck.  the old attempt (at bottom in this pic) as way too big and clunky, but I think the new one is vastly improved.  And yes, the stringers now sit approximately under the rails:


Then it was time to build some trestle bents.  Turns out that Walther's Goo acts like contact cement for wood so I was able to get a forest of upside bents knocked out in short order:


Then it was on to cross bracing:


Once I get these assembled I'll trim them to uniform lengths with a cut-off disk in the old Dremel - or I can just bury the uneven ones in the bottom of the Bayou.

And addressing the visual element of two turnouts on a bridge - I have one throw bar now firmly on terra firma to the "left" end of the bridge (so I'm actually matching about 2 dozen prototype photos I've found).  The other will be placed on a trestle bent, so I can run my HumpYard Purveyance linkage up the backside of the bent (painted black).  Then, I think I can make a great set of bald cypress trees from these:

http://www.modeltrainstuff.com/JTT-Pine-Tree-p/jtt-94294.htm

The two I have are way less dense in the foliage department, and if I carefully make some knees out of Sculpey or some similar "art clay" it will work nicely.  I'm aiming for this:

http://blogs.dickinson.edu/luce09/files/2009/11/41.jpg

with the tracks and bridges running through it.  Given my benchwork height of 50 inches, I'm pretty sure the switches will be unnoticable when I'm done.

[davefoxx]

I took a lot of suggestions from my fellow asshats when I built my trestle last year, and the result was a dramatically improved bridge, thanks to TRW peer pressure.  So, I offer this constructive criticism in the hopes of passing the wisdom along.

I'm still not a fan of the turnouts on the bridge.  First, it does not allow the use of bridge track and the closer spaced ties.  Second, having to operate switches on a trestle doesn't necessarily seem safe, unless you add a walkway.  Perhaps a ballasted deck (double track width) would be the answer for your circumstances.  Alternatively, a double-track-width wood trestle could work and make for a much less complex structure.  The turnouts could then fit easily on the bridge.

As far as the bridge deck, I think you should build your bents and then construct the deck upside down.  The spacers between your stringers don't exist on 1:1 trestles, and, on the prototype, there would be more stringers (see the drawing above).  Also, the joints of the stringers should fall over top of the bents (or maybe overlapped where the angles come together.  I really recommend studying a number of prototype trestle photos and working from there.  Remember, Ed's Law notwithstanding, the mundane and ordinary is usually more plausible in the modeling world.

Hope this helps,
DFF

[Dave V]

DFF speaks the truth.

Unlike most of the asshattery, I lived a few years in Louisiana (Ft Polk) and I agree that wood pole trestles are a must.  But I have to agree with DFF that having switches on them is probably not prototypical or sound engineering.  Even if Ed's Law proves to be true, one or two prototypes in favor in the face of overwhelming prototype against will still create dissonance.

Pennsy did interlockings on bridges (Sherman's Creek at Duncannon for example) but did so atop 4-track wide stone bridges with fully graded ROW on the solid deck.

Your other option if the Bayou must be there is the aforementioned culvert (or a pair).  However, given how prone Baton Rouge is to flooding I would think culverts are more choke points to be avoided.

[Philip H]

Gentlemen,
I appreciate all your input.  I agree with Dave V. that a pole trestle is a required element in this scene, and I have sent many happy hours taking pics of same said in many parts of Louisiana - so first hand observational data is indeed well in hand. I had though about a ballasted deck in some form, but I'm trying to balance a complex set of Givens and Druthers:

Givens:

• Fixed yard throat on "Elkins"
• Removed track as much as possible on Refinery Module
• Two right hand turnouts kindly donated
• A need for something to bridge the short gap between the yard and refinery

DRUTHERS

• Swamp or Bayou scene to allow for practicing of cypress swamp modeling before getting to Devil's Swamp dock on the other side
• Scratchbuilt or mostly scratchbuilt elements
• Aviod removing further track on other areas

So working from that list, I am sticking to the trestle idea.  As you can see from this photo, one of the turnouts is now safely on dry land, and the other is on the back of the bridge, almost across it on the other side:



If there weren't that pesky wall and the need to bend track around it I could probably have moved the switch back to the yard lead side.  As it is, I can get walkways on both the outside track and the outer side of the behind track, and have them look good.  Frankly, since the layout is set 1995-2005 I can plunk one of DKS switch machines down over the throwbar to hide the bell crank from my Humpyard throws.  I can slso get some bridge flex on the front track since its nearly all going to be after the switch.

Down at track level, things look pretty good - though I obviously need to grade the bayou a tad:

[seusscaboose]

lookin' goooood!

more pics!
more progress!

[Philip H]

lookin' goooood!

more pics!
more progress!

yes, well . . . I'm locked in a now 96 hour old battle with two strings of lights on my 9 ft pre-lit christmas tree.  The wife is amused by my temerity.  My kids, not so much.  Still hoping to get some temporary track liad this week to shake this all out.

[C855B]

Catching up...

I have to agree a little with the Daves that turnouts on a bridge and especially a trestle is generally ill-advised. From a prototype perspective, switches are the culprit in most derailments especially in low-speed switching situations, and you don't want to put your crews or equipment in the position of having to re-rail stuff while sinking up to their armpits in the bog.

However, as to "Ed's Law', there is a pretty famous switch-on-a-trestle - the west switch of the wye at Keddie, CA, on the former WP. Technically the points are on solid ground, but all the rest of the fiddly-bits are hanging out there on the structure. Also, the old Sacramento Northern had miles of stuff up on pilings in the Sacramento Delta, including sidings and spur access. It was pretty amazing.

[Philip H]

Mike,
I'm NOT invoking Ed's Law here (or any of its corollaries).  I'm gonna hang walkways on the outside of this thing - with some Berkshire Junction EZ line as the safety cable - so the derailment issue will be minimized (with the usual Atlas turnout tune-ups).  And this is inside my Yard Limit anyway, so slow going will be the order of the day.

[John]

ed law .

http://www.american-rails.com/images/Chessie_GM_HarpersFerry.jpg

[wcfn100]

GN/BN double track main into the old Minneapolis Depot.

http://goo.gl/maps/Cdgv0

NP had one in the Cities as well.

The WCF&N had a turnout on a small trestle at Denver, IA.

Jason

[davefoxx]

Ed's Law, alright, but another reason that I'm not a fan is because the Atlas turnouts will not have bridge ties under them, which will stick out like a sore thumb.  However, since Philip is going to install walkways along the trestle, maybe that visual impact can be reduced.

DFF