It seems to me that the main problem with noise on a layout is not necessarily the type of roadbed you choose, but the fact that once the scenery is in place, it confines the noise to that area and makes it seem much louder than open track with no scenery, where the sound escapes into the room and is minimized by the larger volume of air. If so, it would make an interesting topic to banter around - how to get more air volume under completed scenes.
Or would it be possible to encapsulate the bottom of the layout with a sound deadening material (while still providing easy access to wiring, etc.?)
Frank, Your right. After the scenery is done one is rolling his trains over a drum. Train noise has never been a big concern to me. Now that I plan to install sound in my locomotives it is. For quiet operation the sub-roadbed is a big factor though. I have been using a spline sub-roadbed and it has made a difference as far as sound goes over my last layout that used cookie cutter 3/4 inch plywood with cork roadbed. I've placed foam roadbed over most of this. We have this big roll of plastic bubble wrap my wife brought home for some reason and I thought stapling this under the layout might reduce sound. I think Bob May mentioned that a big part of noise factor was the vibration transmitted through the benchwork and legs of the layout so maybe irregular spacing and legs bolted on with gaskets of rubber or felt might help. In my staging yard area I'm covering the plywood with rubber flooring. I tested this out and it appears to deaden the sound well but I've not laid the flooring in this section over the plywood yet. This area is over a 9' section of book shelving so the front side under the layout will be exposed and its not supported in the same manner as the rest of the layout. The cross members are covered with strips of felt and the plywood was then screwed down. Next I drilled holes through the plywood into the crossmembers that support it, squirted in some glue, hammered in wood dowel pegs and backed out the screws. The splines are attached in the same way but screws were not needed to temporarily hold them in place. The layout sits over rubber flooring as well. It is L-girder but built over what amounts to tall kitchen style cabinetry that will have doors for access and to hide stuff stored under the layout. Since the bench work will be closed off around the front side and boxes full of stuff will fill much of the space under the layout that should have some baffling effect. Another thing that will make some difference is the type of glue used to ballast the track. So far things are very quiet. I don't have any ballast or scenery in or even all the benchwork and track finished, so I don't know if my efforts will result in silent operation. Its taken me three years just to get to this point so I'll live with whatever result I get. Bruce
"Frank Eva" wrote in message news:fOcMb.11146$ firstname.lastname@example.org...
I'm not sure that's true. Seems the varying vibratory frequencies of the different scenery, track, and benchwork components would help to cancel each other out. But we're both just speculating.
Another thing that's occurred to me. One of my other hobbies is woodworking and a while back I built a xylophone. The "keys" have "node points" where they rest on the base. If they touch the base elsewhere, their tone is deadened. These node points are approximately 1/5 - 1/8 of the way in from the ends.
That's pretty close to the points we attach joists to L-girders. Of course, they're fastened down and the xylophone keys aren't, but it does make me wonder.
This sounds like the concept I may attempt to employ in a new narrow switching layout I have in mind! I'll have to check to see how much some cheap cabinetry would cost, and then build the layout on top of it. The latest MR has an added bonus on track plans and one of them uses bookcases with 2" rigid foam as a base - he says he even can allow the foam to overhand 3-6" or so without support. I bet that would be quiet!
BTW, I'm not sure about the sound being dispersed down through the legs, though. I am using cantilevered supports all the way around my current layout, and they are attached to drywall, which in and of itself should have some sound deadening properties, but the difference in noise is very significant between the completed areas and the incomplete.
We've considered benchwork that will be covered with scenery, but how about bridges? At one time, I had an open-deck girder bridge, that was really noisy when a train went over it. I had made it from an Atlas deck bridge that I turned over and glued wood ties to; the track was CAed to the wood ties. The underside of the bridge was open, but I didn't mind because it couldn't be seen. So, I tried several experiments to try to deaden the noise. First, I tried a piece of rigid foam cut to size and glued underneath - no significant improvement. Then, I tried covering the foam with a thin piece of KS metal. Still no difference. I finally gave up, especially considering that anything I did come up with would obviously not apply to any other type of bridge.
Actually, according to the demonstration I got in college from engineering professors specializing in vibration and noise dampening (I was a music ed major, so it did have practical applications for us!) the best way to deaden sound is to make it be transmitted between materials of different densities. For example, alternating foam and plywood in your base material. (Remember the foam layout on top of the bookcase that was so quiet, and the layout that was quiet everywhere but the bridge?)
If you DO tighten down the bars (that rest on either rubber or felt washers) you almost completely kill the sound by keeping the bars from vibrating. However secret of the mallet percussion (xylophone, marimba, vibrophone) is the resonating tubes under them - it reinforces the sound waves. To some extent, putting a hard fascia all around the layout re-creates this effect, the deeper the fascia the more pronounced the effect. Of course, it's not tuned to the resonating frequency of the layout (unless you're REALLY unlucky!) but it does exacerbate the problem slightly.
My layout is pretty quiet... of course, it's N scale on Woodland Scenics foam roadbed and risers (both different densities) on hollow core doors (hard skin, cardboard honeycomb core) and a cloth skirt all around.
BTW, Larry... Didn't I see you on TV yesterday on PBS? Nice "train set"!
Joe Ellis ? CEO Bethlehem-Ares Railroad - A 1:160 Corp. ___a________n_mmm___mmm_mmm_mmm___mmm_mmm_mmm___mmm_n______ ___|8 8B| ___ /::::: / /::::X/ /:::::/ /:::::/|| ||__BARR| | | /::::::/ /:::::X /:::::/ /:::::/ ||
---------------------------------------------------------------- [(=)=(=)=(=)=(=)] |_________________________| [(=)=(=)=(=)=(=)] =============Serving America's Heartland Since 1825=============
I once build a demo layout for a hobby shop. I used all their products including Tru-Scale ready track. Ths noise was incredible!! The best results at the time were coark roadbed on homasote on plywood for being quiet. When the shop went out of business he sold the layout before I could get there. Someone got a heck of a deal. The hobby shop became a computer shop........ times, they are achangin'.... but not on MY layout... (VBG) Paul
Track noise is often transmitted to the baseboard and from there throughout the layout by the material bonding the ballast down. This is often dilute white glue or other adhesives which set hard, so are good sound transmitters.
An alternative is 50/50 mix of latex glue and acetone, which bonds the ballast quite firmly but does not set hard like white glue. The only problem with using acetone is that it's essential to pour the mix in an extremely well ventilated area, or even outside if possible. And in any case wear a respirator (not just a dust mask).
It evaporates very quickly, leaving only the latex glue. The acetone is simply to allow the latex to flow quickly, like the usual water/glue mix. But you need the area to be well ventilated or do it outside to allow the acetone vapour to dissipate.
However you'd only do short sections at a time since it dries faster than white glue and you don't have much time to correct any mistakes. It's well worth the effort as the noise reduction is superb. You can hear the clickety-clack over joints at the joint, rather than off all surrounding structures.
I haven't done any ballasting for a while, but the brand I used last time was Mehron. Just about any liquid latex will do so long as it dries clear and doesn't stay tacky when "dry". Some of them will dry an amber colour, which can be a problem if you're using light coloured ballast. Some latex adhesives, such as used on carpets, stay slightly tacky.
I would suggest looking in your local hardware or art/craft supply shop and experiment on a length of flex track.
It was, I believe, Ch 16 here in Dayton, Ohio... they were showing a program called "Great Scenic Railway Journies". There was a segment on the Cuyahoga Scenic Railroad, and the engineer's name was Larry Blanchard.
I know some folks like to use a spray of alcohol as a wetting agent before the glue goes down, but I haven't had good success with this. It would seem that it dries faster than you can get the glue down, or you may have to do very small sections of track. Regardless, I'm wondering why simple water to dilute the latex glue wouldn't do the trick?
Just a spray won't work - you have to saturate it. And you can still only do a couple of feet at a time. I use half water, half alcohol, and a couple of drops of Joy.
And simple water won't work. Its surface tension is too great. That's the whole reason for all these strange mixtures - to reduce the surface tension so the white glue or matte medium or latex or whatever will thouroughly penetrate.
Yes, I thought about that after I left this message. I always add some dish detergent to my ballast glue. Regardless, would the "latex" glue, diluted with water and detergent have the same insulating effect as the glue/acetone mix?