DSchmitt NP2626 That is an interesting video, in places on the bridge, the fire was hot enough to bend the rail! I see places for water barrels, but no barrels. Many narrow tunnels also have refuges. Slots in the walls where a person can stand clear of the tracks.
NP2626 That is an interesting video, in places on the bridge, the fire was hot enough to bend the rail! I see places for water barrels, but no barrels.
That is an interesting video, in places on the bridge, the fire was hot enough to bend the rail! I see places for water barrels, but no barrels.
Many narrow tunnels also have refuges. Slots in the walls where a person can stand clear of the tracks.
I understood what they were for and why barrels are not used anymore.
NP 2626 "Northern Pacific, really terrific"
Northern Pacific Railway Historical Association: http://www.nprha.org/
They are "refuges". A place to escape to for people on the bridge if they are caught by a train.
I tried to sell my two cents worth, but no one would give me a plug nickel for it.
I don't have a leg to stand on.
Former Lawyer
Those were amazing videos! Thanks.
For those who want to see them, highlight the link, then right click on it, then select 'Open Link' or words to that effect.
They also gave me some more ideas on how to build the bridge on the far left of my layout.
Dave
I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!
There are youtube videos of the Cisco Bridge fire in 2001
https://www.youtube.com/watch?v=XdJmvq6mzN4
Protection of the ties was the primary purpose of the fire barrels on a steel bridge. But they date from a an era very different from today.
For the fire barrel to be of use, it must contain water. With evaporation that means a maintenance task of regularly topping it off - won't happen. In more secluded areas they were also tempting targets for local amateur "marksmen" and bullet holes mean early drainage. There must also be somebody there to carry the water to the fire.
Furthermore the limited quantity of water, and even smaller pail to carry water to where it is needed, means that once a fire has gained a foothold the fight is already lost. A man looking back from a caboose (remember them) or a patrolling sectionman behind a train might notice a smouldering tie in time. But a standard fire extinguisher carried on locomotives and hi-rail vehicles will be more effective.
NP2626 I have a question on the steel viaducts I've seen shown in this thread. While I can see the need for Fire Barrels on a wood trestle, where the used on steel structures, also? If son it must have been for the ties, as nothing else would burn on a steel bridge.
I have a question on the steel viaducts I've seen shown in this thread. While I can see the need for Fire Barrels on a wood trestle, where the used on steel structures, also? If son it must have been for the ties, as nothing else would burn on a steel bridge.
NP:
That's my thought, also--to protect the ties. I've seen the fire barrels on viaducts here in the heavily forested Sierra Nevada, but I'd hardly think they'd be much protection in case of a forest fire, lol! So I'd conclude that it's to protect the ties in case of a hot-box.
Tom
Tom View my layout photos! http://s299.photobucket.com/albums/mm310/TWhite-014/Rio%20Grande%20Yuba%20River%20Sub One can NEVER have too many Articulateds!
Regarding the third bridge on the far left of the layout, I have decided to forgo through truss construction in favour of simple ME deck girders. The bridge is about 275' long so, according to my drawings, I should be able to use 3 towers @30' ea. plus 4 x 50' deck girder spans to create the bridge. The end girders may have to be trimmed down but that is no big deal.
At least that's the plan for now.
Thanks again for all your help.
I have a question on the steel viaducts I've seen shown in this thread. While I can see the need for Fire Barrels on a wood trestle, were they used on steel structures, also? If so, it must have been for the ties, as nothing else would burn on a steel bridge.
Hi Tom
You certainly are not butting in on the conversation. Your bridge looks pretty good too! Gives me a good idea of what to expect, although the 25.6" radius may look a bit odd.
As far as the 50' section, I spent some time drawing up a few different possibilities for the bridge and it became pretty clear that the 50' spans were unworkable. Even a single 50' section like Bob K. had suggested won't work without a lot of tie overhang.
One advantage to using all 30' sections is that it fits in the available space almost perfectly.
Thanks for your input. Saved me some money by not buying a 50' section to experiment with.
Dave:
Hope I'm not butting in here, but I notice you mentioning about getting a ME 50' girder section for your bridge. Since your radius is about 25", you'll probably find that the 50' section will be a little too big for the radius. This is my curved ME viaduct over Deer Creek. The radius is 36" and the sections are all 30'. I was going to have a 50' section in the middle, but even for a 36" radius, it would have been too long.
I think you'll be better off sticking with 30' girder sections all the way around. Tom
I think you'll be better off sticking with 30' girder sections all the way around.
OK, I bit the bullet. I found all but one of the pieces that I will need for a 7 section single track deck girder bridge at fair prices so I bought them. They are all coming from one seller so I can save some on the shipping, and the total is less than $100 Cdn so I should be able to beat the import duties.
"He who hesitates is lost".
Now I have to go to work on the wooden trestle, but I think I have already solved that problem with a JV Models #2016 curved trestle kit.
There is also the third bridge against the back drop. It has a 45" radius which simplifies things in some respects, but the whole structure has to be 275 scale feet long, give or take a few feet. I may be a little insane here but I would really like a through truss structure. I'll have to spend some time looking at the Central Valley bridges with the removable superstructure.
No Wayne!
You're all wrong on that. I intend to detail the backs of all of my buildings, even the background flats! NOT!!
Seriously, you make a good point. The camera doesn't lie so if you want to capture those normally unseen angles it pays to have detailed the backs of things that are closer to the front of the layout. Personally, I just like to know the detail is there, which I believe is contrary to the views of one master modeler (John Allen?) who advised against modelling what can't be seen.
grinnell....[In my case only one side is visible, so I'm only doing the girders and stripwood on that side and my spline is the full width of the deck on the back side.]
There's certainly nothing wrong with not detailing the unseen side of things - I have a lot of structures with three visible sides, and a fourth, which looks like this:
or this:
These aren't visible, though, as they're against the backdrop.
However, there are places where something's visible from the aisle:
...and also visible from an angle not available in person, but readily seen by a camera placed on the layout and pointed towards the aisle:
This, of course, doesn't happen unless you bother to try it, but it can offer a view that you'd otherwise never see.
Wayne
Hi Grinnell
Thanks for the suggestion about using a ballasted bridge. It would certainly be a less expensive solution.
For some peculiar reason I don't like the appearance of ballasted decks. Please understand that I am not being critical of your methods. I just have this picture in my mind of how I want the bridge to look. I don't like the looks of stone bridges either, at least for my purpose. In my setting they would be really out of place.
I'm sure some of you are saying that I am a pretty fussy guy, but hey, you know the phrase "its my railroad and.....". Maybe I just like doing things the hard way.
Instead of an open deck steel trestle, a ballasted deck allows you to use a carefully cut piece of 3/4" plywood, about an inch wide, to act as a support spine along the length of the bridge. Micro Engineering girders are used to 'face' the vertical surfaces of the spline. Strip wood is used to make the narrow strip of decking that is outboard of the girders. Regular cork roadbed produces the ballast surface. Temporary vertical 1x2s can be used to support the bridge and get trains running until you are ready to replace them with Micro Engineering towers. Insteaed of buying the 'bridge kit', you only need to buy the girders and then the towers. This is how I'm doing a couple of steel trestles. [In my case only one side is visible, so I'm only doing the girders and stripwood on that side and my spline is the full width of the deck on the back side.]
Grinnell
Bob
I will give a 50' span a try when I get the actual parts, but as I mentioned above, the initial drawing doesn't look very good.
I'd love to increase my radius on the bridge but if I do it there I have to reduce the radii on adjacent curves. That would put them below 24" and I am trying to stay above 25". I don't plan on running any long locomotives but I do have a set of Walthers 85' passenger cars (in the CP 'Canadian' livery of course). I'm hoping I can get them to run on 25" radius.
hon30critterWayne - you mentioned that I will need 6 towers to do the bridge in 30' sections. My calculations suggest three towers with 30' deck girder bridges between them and on either end. That is a total of 7 - 30' sections which equals 210' (actually a little less on the track center but that's ok.
Doh! You're right, Dave. I did a quick sketch, forgetting that each tower is a 30' section itself. Three towers will do it - my version woulda had more legs than the Rockettes' chorus line.
I think my next step will be to order one tower with the 30' deck girder bridge, a second 30' deck girder bridge, and one 50' deck girder bridge. I already have the ME bridge track. That way I'll be able to see how much the ties overhang.
Wayne - you mentioned that I will need 6 towers to do the bridge in 30' sections. My calculations suggest three towers with 30' deck girder bridges between them and on either end. That is a total of 7 - 30' sections which equals 210' (actually a little less on the track center but that's ok.
I also did a drawing using three 50' sections but, as predicted, the tie overhang was a little extreme. I'll still test it with the actual bridge parts.
As Dave mentioned several posts back, the gantlet track wouldn't be a viable option for his situation, as one track is the spur to a mine. I'd guess, too, that it would involve hand-laying the track on the bridge - not necessarily a big deal, but...As for stone or concrete arches, either would be a good option for the main track, and could probably be scratchbuilt for less than the cost of the M.E. parts. It could also use regular flex track, since it would be a ballasted deck-type. Because it's on a curve, it would have to be built wide enough to clear the longest equipment using it, since there'd need to be curbs of some sort to retain the ballast.I think, though, that the spur line is a great candidate for a wooden trestle (although if I were building it, I'd use styrene).
I agree w/ Wayne. the 50' girder span could be used, but he tie overhang would be a bit excessive for your radius. If you could increase the radius, it would be a nice feature to at least have a 50' mid span between towers. Your radius is already allowing for some serious "mitering" of the open girder sections, where it needs to meet square tower support beams.
Modeling B&O- Chessie Bob K. www.ssmrc.org
Two types of bridges were not mentioned, both of which can be curved, a stone arch bridge and a concrete arch bridge.
Dave H. Painted side goes up. My website : wnbranch.com
The deck girders, once assembled, are the same width as the top of the towers - 8', while the M.E. bridge track is 10' over the tie-ends. You may have to use all 30' girders to accommodate the tighter curve (the towers are topped by 30'-ers) so you'd need 6 towers for your 210' bridge.Another thing to keep in mind is that the girders on the inside of the curve will need to be shortened, but not those which are atop the towers, as that would leave them unsupported.
I'm sorry, I didn't use the proper terms. I meant to use the deck girders. I'll correct my post.
Does that make it feasible? How wide are the deck girders?
Thanks
I don't think so, Dave. The tall viaduct is designed to be used with the deck girders, not the through ones. You might be able to widen the support towers, but it probably would use-up a second kit's worth of tower material.
The advantage of the deck girders is that they don't limit side clearance, especially important if your curves are fairly tight.Here's a view of another bridge on a curve which better shows the relationship between the tops of the towers and the bridges which they support.
I have come up with a plan for the mainline steel bridge but I need to clarify some dimensions to make sure the design will work.
I am basing the design on Micro Engineering's tall steel viaduct towers and 50' (Edited to use the proper description) deck girder bridges, not ballasted. I need to know how long the track is on the top of the towers themselves. I'm guessing at 30'. I also need to know how wide the bridge sections are. Based on my calculations I would need them to be a minimum of 14.5 scale feet - approx. 2".
Here is what the bridge would look like based on the above dimensions:
Will this work?
Thanks again for your help.
Mark
I intend to read your thread over again as I get further into the design. Having different lengths is definately an option, however it would have to be the spur bridge that changes. The mainline bridge is trapped between two turnouts so it can't get any longer and I want it as long as possible.