I haven't found much on this subject on the internet nor in the search community to the right, and I am especially interested in pictures of a ballasted trestle on your layout if you have such an animal.
I would like to see pictures of how the ballast is kept in place on the sides and underneath; I have a ballasted curved deck that I am going to turn into the deck of a trestle.
Thanks.
The St. Francis Consolidated Railroad of the Colorado Rockies
Denver, Colorado
50' Ballasted Deck Pile Trestle (less ties) There is a deck to support the ballast. Best exsample I could find.
Johnnny_reb Once a word is spoken it can not be unspoken!
My Train Page My Photobucket Page My YouTube Channel
The only place you find ballast on a wooden trestle bridge would be at the approaches.
Once you are into the span there is no ballast. The bridge has to support enough weight why would you want it to support all the weight of the rock as well? You can actually see down thru the span to the terrain underneath. Ballast on the roadbed is used to keep the ties from shifting and moving. On a trestle the ties, stringers and other wood parts are held together with bolts, nails or spikes.
Typical trestle bridge construction has a stacked set of stringers running spanwise from bent to bent. Across these stringers are laid the bridge ties. The pitch (spacing) between the ties is much closer together than on the roadbed over solid ground (perhaps a bit more than the width of a the tie itself). this is to help distribute the load.
This may help understand.....
-G-
In railroading, you should never say 'never', but in this particular case, the examples worldwide could probably be counted on one hand. It would require stripping all the rails and ties, laying a subroadbed over the stringers (weight), adding some ballast, laying ties, and then topping up and grooming the ballast. With all that extra weight, I doubt they'd use a dynamic ballast adjusting machine.
So, I would say that if you are modeling anything earlier than about 1960, and assuming the road wanted to continue to use a wooden trestle, and assuming the trestle was assessed and rated for the extra tonnage and consist typically using the bridge.....you can see where I am headed.
Crandell
As I do my daily commute between Colorado Springs and Pueblo, there are perhaps a dozen (or more) ballasted trestles along the D&RGW/Santa Fe main line rights of way that are easily visible from I-25. Most of these still have at least some wood stringers and/or pilings. All are very short (about half a bent high) over what are normally dry washes in the high plains/desert. And they are short in length, rarely more than 2 sets of pilings, occasionally 3 or 4. I've never taken a closer look at their construction, except to note they had some wood pieces and ballasted decks. Sorry, no pics either.
The parallel lines are now a heavily-trafficed joint operation between UP and BNSF.
Fred W
I built an SP style open deck pile trestle with ballasted track. Found plans in the SP standards book augmented with photos taken of a nearby trestle.
Guy
see stuff at: the Willoughby Line Site
Thanks for all your responses.....and while I understand the implications of heavy ballast as a stress (unnecessary perhaps) on trestles, on the other hand.................
GUY BABY, YOU DA' MAN!!!!!! That's exactly what I was looking for! Thank you, thank you!.
Somehow I just knew I'd get a lot of good answers on this wonderful forum!
Hiya Fred, I live in Denver and I'll be darned I've seen those a thousand times and it never occurred to me that they were ballasted. I'll check 'em out with my drawing pad in hand next time I'm down south.
Thanks!!
FYI: Open deck ballasted trestles are very common out here in the western USA. I personally know of many of them within a 30 minute drive from my house. Most of these are still in use. The Southern Pacific and other western roads (WP, Santa Fe) used them quite often. Many of them were/are taller than one bent and some traverse quite a distance.
The trestle in my pics above is modeled after the 9th street trestle in Modesto, CA on the WP.. This trestle was easily a thousand feet long and was roughly 50 ft high. It was used up until the 1980s and unfortunately was burnt to the ground in the late 1990s...
The Southern Pacific standards book lists lots of different classes, designs and specs for these and many other styles of trestles. Info listed includes lumber size callouts and critical dimensions for most parts of these structures.
As some have posted here, ballasted (closed deck) wood trestles were common in any era. They were more common however in areas that were fire prone as ballasted decks were less likely to catch on fire from sparks from the locomotives or cars than a bridge entirely made of wood with bridge ties (open deck). Another reason ballasted deck bridges were preferred by some engineering departments is that it was easier to make a smooth track transition on and off the bridge. We had some ballasted deck trestles in the East too and up in Canada. There are excellent, well written books on railroad bridges including modeling them. Both Kalmbach and Carstens have published them, including plans.
The October 1958 issue of MR has an article on wood trestle construction. It includes a cutaway drawing of a ballasted deck showing the construction in detail .
Besides fire safety, which is also mentioned, the article states that ballasted deck trestles provide a smoother ride than open deck trestles.
Recovering former former model railroader.
Ballasted trestles/bridges are extemely common in the western U.S. Here are SP, ATSF and Grand Canyon examples.
The SP constructed the ballast floor and side boards from 4-by-12s. In addition to the several 8-by-18 stringers below each rail, single 8-by-18 stringers would also be placed under the edge of the ballast floor.
SRN The October 1958 issue of MR has an article on wood trestle construction. It includes a cutaway drawing of a ballasted deck showing the construction in detail .
First of all, thanks to everybody for their responses and great input.
Second, to SRN particularly, we can all probably write this story together:
(1) I have hundreds, maybe thousands, of train magazines;
(2) amazingly, I have only one Model Railroader issue from 1958, and it's July
(3) what to do??? EVIL EBAY OF COURSE!!!
(4) within seconds I see eleven issues from 1958, (only JULY is missing!) and I bid on them.....
I always wanted 1958 Model Railroaders, so now don't anybody go and outbid me, including any of those snipers who are extending a series of comments on the subject of buying rr stuff on ebay!
I must say that I have had my eyes opened with the responses to this thread. I had never encountered such wooden trestles, but between a PM or two and those responding with examples, it seems I was mistaken; even today they are more common that I had understood.
selector I must say that I have had my eyes opened with the responses to this thread. I had never encountered such wooden trestles, but between a PM or two and those responding with examples, it seems I was mistaken; even today they are more common that I had understood. Crandell
Is there anyone more admirable than a real man who's willing to learn?
It's very kind of you to say so. Thanks.
SRN The October 1958 issue of MR has an article on wood trestle construction. It includes a cutaway drawing of a ballasted deck showing the construction in detail . Besides fire safety, which is also mentioned, the article states that ballasted deck trestles provide a smoother ride than open deck trestles.
Well......having NOT been outbid, and having got my issues of 1958 off the ebay, I can say this article is EXACTLY what I was looking for.
It turns out the added stress of ballast is compensated for by extra stringers running under the deck more or less parallel to the tracks, and, indeed, the ride was intended to be much smoother, and, again, the ballast was intended to cut down on the risk of fire.
Looks like about thirty percent more stringers according to the calculations in the tables, and the ballast is held in place (presumably to prevent side to side migration) by 4" by 8" wooden ballast retainers.
The first part of the article has some absolutely fascinating diagrams of different configurations of stringers on the deck, including stringer configurations for my ballasted decks I'm interested in.
Thanks to all who contributed to this topic, and I will post pictures as soon as I get something built later this spring and early summer.