When/where does track have ballast on bridge or trestle?

[Zox]

You win, you win.

Cool! Can I take my prize in NZT merchandise? 

[jmlaboda]

The CSXT Big Bayou Canot bridge was a swing bridge that never was motorized, having welded rail installed prior to the incident.  Swing bridges, due to the weight involved, would typically not be ballasted.

[nkalanaga]

The Milwaukee preferred ballasted deck trestles for short spans out west, and they certainly weren't a high speed railroad.  I think they did it for the "track geometry" reason.  They would have had a hard time getting the track crooked (kinked) enough to match the rest of the main if they'd used open decks. 

Incidentally, they also liked round "river rock" for ballast.  Most ballast is jagged, so that it digs into the ties and holds them in place.  At least in the later years, the MILW is reported to have used a lot of river rock to keep the ties from wearing out as fast...

While many of their larger steel trestles also had ballasted decks, as far as I know the Beverly bridge in Washington, deck/through truss, had an open deck.  Does anyone know for sure?

[Chris333]

A couple years ago CSX replaced a bridge in Youngstown, OH

They replaced this:
http://binged.it/10fOOy6

with this:
https://maps.google.com/maps?q=youngstown,+oh&hl=en&ll=41.08765,-80.633174&spn=0.001815,0.00305&sll=40.365277,-82.669252&sspn=5.314769,12.491455&t=h&hnear=Youngstown,+Mahoning,+Ohio&z=19

2 for 1 special:


http://www.brayman.com/CSX-Youngstown
http://www.brayman.com/CSX-Youngstown-Demolition

[robert3985]

Here's my favorite ballasted deck bridge at Curvo Utah where the U.P. crosses over itself going west to become left-hand running about 55 miles to Ogden.

It's been ballasted for decades, but I believe that when it was constructed it was not.  I might be wrong and I'll do some research into it tomorrow.


Here's another view showing the west portals of the twin tunnels at Curvo.  I'm building an 8' photo diorama of this remarkable place and it's about 1/3 finished.


These photos are by Don Strack who got permission to trespass the private hunting preserve to take these photos which can be seen on his website: http://donstrack.smugmug.com/UtahRails/Union-Pacific/Weber-Echo-May-2003/14108553_GXWkmJ#!i=1039884926&k=TR39t69  along with a wealth of additional information about railroads in Utah.

[rogergperkins]

  It appears that with poetic license, I can do about any configuration using the Atlas True-Track over a deck "bridge."  Because the span is 19 real inches, I anticipate a minimum of 3 supporting structural elements.  In my inventory, I discovered a Rix high way bridge, but would need several of them if I elect that option. 
I see a possible answer: N-PLATE GIRDER BRIDGEs.
Four of these from Atlas would span the river area and all the True-Track to be inserted. 
Now for the pier which would look best if they were the ones for the Atlas Stone Arched bridge.

[randgust]

I'm not the card-carrying structural PE in here, but I do know that there's a point where when the span length is long enough, the web depth of a plate-girder bridge results in a structure so heavy that your dead weight of the steel begins to seriously push the design standard over to a deck truss instead - more strength, longer span, less steel.     It also depends on the clearance underneath whether it's going to be a through truss or a deck truss, through girder or deck girder.   

You can have massively long scale-sized spans (the Canyon Diablo is one of them) but not as a deck-girder.  Sounds like you're spanning an opening or an aisle.   Cheap way out there is to simply model the 'bottom' of the canyon/river/whatever and add piers as necessary so that the bridge itself isn't the structural element across the 'hole', the benchwork is and the bridge is on it.

Once you get a feel for the span length and your own railroads standards you can get a pretty good idea what kind of bridge is appropriate.   The tendency today is for a lot of precast concrete beams, more piers, ballasted decks, and deck-spans.

That picture that Chris put up is just excellent.  Makes the point exactly.

And there's always inexplicable practices and results.   Today's Texas State Railroad had every ancient wood-pile trestle replaced with UP standard design concrete ballasted deck trestles, all precast.    And it's basically a light-service tourist railroad.  But that was the applicable 'state standard' they found, so that's what was put in.  On the other side, I think you can still find a lot of ballasted wood-deck pile trestles on the ATSF transcon, standard design, and in dryer areas they've held up pretty well.

We've had to design the tie-replacement plans in here for curved direct-fixaction steel bridges; i.e. like that one in Chris' shot on the left.   The ties have to be canted for superelevation on a curve.  If the curve is anywhere on the spiral, EVERY TIE has to be individually calculated for dimension, cant, and superelevation, as well as notched to fit the stringers underneath as they are straight, then fabricated and numbered by the contractor to about 1/8" tolerance.   Freakin' nightmare.  When the bridge ties give out, yeah, serious time to think about replacing the entire bridge.  As a modeler I had no idea it was like this, but looking at the reconstruction plans and the replacement cost per tie every alternative was examined.   It would have been so much simpler to have a ballasted span and just send in the tamper.

[nkalanaga]

The increasing web depth isn't just a weight issue.  Beyond about ten to twelve feet, it becomes very hard to transport such a girder.  A good "rule of thumb" for a railroad bridge is that the girder depth should be 1/10 to 1/8 the length, so 80 to 100 feet would be about the maximum. 

For a ballasted deck girder bridge, one can try the Micro Engineering girders.  They are (or used to be) sold separately, and one wouldn't need all of the cross bracing and stringers.  The ballast will hide everything, so one can glue the girders to the roadbed.

[rogergperkins]

I have searched for photo of Micro-Engineering plate girders with no luck, thus I do not know if they are an option.
The link(s) on e-bay, that I found, did not have photos.  M-E does not seem to offer them per their website.

[Chris333]

http://www.modeltrainstuff.com/Micro-Engineering-N-80-Plate-Girder-p/mec-80-170.htm
http://www.modeltrainstuff.com/Micro-Engineering-N-80-171-40-Plate-Girder-4-each-p/mec-80-171.htm

[rogergperkins]

Chris333, thanks for the links.  They look great.  Do not know how I missed them as that is one place I searched.
Are they just the side portion?

[Chris333]

Yeah you just get the girders. They sell the deck as well:
http://www.modeltrainstuff.com/Micro-Engineering-N-80-Concrete-Bridge-Deck-p/mec-80-041.htm

But you could make the deck out of balsa sheet lined down the sides with a balsa strip if you want. Then spray it gray.

[Carolina Northern]

Roger,

How about some Unitrack viaduct? Take the track off by removing the screws and pull any track you like on it.
I've sliced the grirders off when I needed a quick bridge.

[Coxy]

These photos are by Don Strack who got permission to trespass the private hunting preserve to take these photos which can be seen on his website: http://donstrack.smugmug.com/UtahRails/Union-Pacific/Weber-Echo-May-2003/14108553_GXWkmJ#!i=1039884926&k=TR39t69  along with a wealth of additional information about railroads in Utah.

Thanks for this reference. Curvo is a great spot with a lot of great engineering in a very compact space - two tunnels, overlapping tracks, interesting bridge construction, through trestle support. The Curvo area is a bit of a mystery spot due to unwelcoming locals so pics are in short supply.

Now, back to the thread on ballast on bridges...

[Bobster]

Roger,

Diving North along the river may only get you some small wood bridges with ballast.  Maybe on the right between Mossville and the Caterpillar plant there is a steel bridge.  Get a Peoria County map it has a lot of smaller roads.  The County used to have excellent ones downtown at the courthouse.  May I suggest if you drive North turn right off Hwy 29 just past Caterpillar Mossville. Follow the Old Rock Island (Iowa Interstate) up to Chillicothe.  Just north of the Old RI station there is a bridge where the Santa Fe crossed over the Rock Island. Using the map, so you don't trespass, follow the Ex Santa Fe East to the River.  Heading back West see how the Santa Fe crossed over Hwy 29 then headed West up Edelstein Hill.  There is probably a right turn then a left just before you head up the bluff to keep you close to the tracks.  I just can't remember.  The name North Hampton (just a few houses) comes to mind.

Next consider the bridges South between Washington Street and the river all the way down through Bartonville.  Once near Bartonville head up Creek Road and you will find bridges from the C&NW (UP) and CB&Q (BNSF) era all the way up to Pottstown.  Turn left on route 8 at Pottstown and there should be a couple bridges across Kickappo Creek near where I-474 crosses.  There may be a bridge just west of Edwards but I can't remember.

This should give you plenty of rail bridge inspiration / information close to your home.  Not B&O specific but basic bridge construction information.  You could always track down an old map and head East from Beardstown to see what's left of the B&O.  I don't remember B&O in the Peoria area but it is your railroad.

Now having said all of the above 2 last things.  First, Yahoo has a Peoria Rails Group.  Join it, they should be able to help.  Second, all of the above is from memory and I have not lived in the area since 1986.  I frequently bicycled all the above roads in the 1970's to mid 1980's.  I know a lot has changed.  I suspect when the old Franklin Street Bridge was torn down the old rail bridge next to it was too.  I'm not sure how many rail bridges cross the river anymore but I'm reasonably sure the one with the wye is still there.

I hope this helps and happy modeling,
Bob