I own a BLI steam locomotive and I kinda noticed the sound was just not the best it could be. The sound is very realistic,but it sounded wierd in the tender kind of an echo sound. OK here is the cheap fix to improve the sound. I stuffed the tender full of cotton stuffing like you would use in a stuffed animal.I think the sound is much better now! I would not recommend this for a diesel since the cotton would tangle up in the motor,but its fine inside the tender where there are no moving parts.the cotton stuffing can be purchased anywhere that sells crafs supplies.and its like 1.50-2 dollars for a huge bag!
Thanks for the ideal, I’m going to have to try it.
I’m going to wait awhile and see if you have a heat issue first. 
Let us know, please.
I read a post sometime back from a guy who said he tucked some cotton inside the back of the speakers for a similar effect. I haven’t tried this though… to me it doesn’t look like there’s room inside those speakers to stuff anything! Plus I worry about damaging the speaker. However I may give it a second look next time one of my BLI’s is in for a little TLC.
Virginian makes a good point. I have no idea how hot those decoders get in operation. Something to watch out for.
i didnt take the heat into consideration.I will keep an eye on it.I ran the engine for an hour after I put the cotton in and there was no problem.
Dave, it isn’t the first hour, and maybe not the fifteenth, but your decoders WILL succumb to heat eventually, and probably well before the statistical life expectancy of the unit. If you can find a way to place the decoder(s) in a little compartment of their own that has vents or open ends to allow circulation, you will not have to worry.
I think your idea has some good sense to it, especially if you achieve your aim of improving the sound noticeably. However, the trade-off might be a useful life reduction of around 60-70%!.
To avoid the heat issue, another solution is to get the thin foam with self adhesive backing. Line the flat surfaces of the inside of the tender. That will stop the echos and still allow air space to help cool the electronics.
“Stuffing the BLI tender with cotton” ‘Changes’ the sound…
It absorb’s some higher frequecies.
It reduces resonant standing waves.
It raises the cavity resonance.
Whether this “improves” the perception of sound, is up to you.