After finally getting the lower hidden level of my layout laid down over the past week, I have gone as far as I can go for right now. I got out a P2K GP7 that hasnt been put together yet and took it for a test run over this section. Half of the lower level is hidden under a plywood sheet that holds the upper level town, and I started the locomotive under this. Going at half speed (to check for track problems) the locomotive horribly loud. The track is on Woodland Scenics trackbed and I thought that P2K locos were supposed to be fairly quiet. What can I do to get rid of the noise?!?
It might be because you built on plywood. I use homasote which is a very sound dampening road bed. I never have run a P2K. You might try putting the locomotive together, though that shouldn’t matter too much. Is it the locmotive or is it resonating form the plywood and road bed. I think that is why foam is such a popular base for layouts.
It is probably the sound being echoed off of the upper deck. Roadbed alone is sometimes not enough sound deadening. It’s probably too late to do you any good, but I put two layers of Sound Board on the Cochise & Western Model Railroad Club’s HO scale layout and the only sound we can hear is from the metal wheels on metal rail.
You’re right – Proto 2000 locomotives are very quiet when out in the open and running on sound deadened trackwork.
If you have room, you might consider gluing acoustic ceiling tile to the bottom of the upper level’s plywood to dampen some of that echo.
There was a topic just the other day about how to quiet down a noisy loco using a machining compound, but I can’t seem to recall what it was called. Hopefully someone will come along that does and fill you in. Meanwhile, you might try doing a topic search.
Nope, foam has serious noise problems too. We made a modular layout with foam base. It acts like a giant drum head and echoed up and down the Mall we were set up in. The metal wheels made it worse. We put on a double skirt to try to contain it. We had to go back and add “soft” foam-rubber to the bottom to quiet it down.
I was actually just running a P2K GP7 10 minutes ago, and I was thinking “Wow, this is quiet” so it must be your arrangement. I would put some cork roadbed, or homasote, under your track, and see if it gets any better. It could be a good thing, as you will be able to tell when it stops[:D]
Matthew
You might try “shoreing up” the plywood in that spot. What can cause a sound problem is a span of anything (plywood, foam, plaster, etc.) that can vibrate in sympathy with the loco as it runs. That is exactly how a violin makes its sound. With violins of course that is usually a good thing (unless it is being played by beginning students in which case it will sound like the draging of a horses tail across the intestines of a cat - which is of course, what it really is anyway). You don’t say how thick the plywood is or how far apart the supports are, or how heavy your supports are. But, if your plywood is not supported well, it can become a soundboard for your trains. I think that is what is happening.
I used Woodland Scenics foam road bed on top of 3" blue foam board, was nice and quiet until I adhered the roadbed to the foam with glue, its like the sound amplifies.
Yep! When you glued it down you created a Tympanic Membane or a Sounding Board that ampifies the sound. The answer is to stop the foam, plywood, or other material from vibrating by making it rigid and unable to vibrate. It is the same as why you get little sound from an unplugged electric hardbody guitar but lots from a light acoustic one.
P2K engines are known to have problems with cracked axles. Mine used to click and clunk, now it whines. If you’ve got a rumbling sound, it’s probably more layout-related, but other noises might be coming right from the engine.
Whatever noise it makes, though, will be trapped and bounced around between your layers, and will all come out the front. The guitar analogy is a good one.