"Railsounds" Question...

Those volume pots are like old radios that have volume static. Dust , dirt and whatever interfere with electrical performance. Try turning the volume knob maximum left and maximum right numerous times. It’s worked for me. Good luck. 

CRC electrical cleaner...found near everywhere.

Spray, turn some, repeat.

Do you own a multi-meter to check the pot with. (potentiometer)

It's normal, my observation with the manual volume control is it's pretty touchy.  There's a good reason for that, they used the wrong part for the volume control pot!  For real audio controls, the pot used is called an audio taper, that's for a good reason. All the train manufacturers use a linear taper pot for reasons that I have never understood, it's the wrong tool for the job!

Here's a chart that illustrates the difference, the Linear is the black line, the audio taper pot is the blue line.  You'll notice the first half of the pot travel changes the resistance only about 10%, that's because most of the apparent volume change happens right there.  Sound intensity is logarithmic, so the apparent volume changes very rapidly for the first 10% of the pot value and much less for the remainder.

Bottom line?  The volume control is working as designed, it's just not a very good design.

Okay all, thank you. I will clean the pots and just live with it as is. 

Mark in Oregon

It depends on what generation product we're talking about. Up through the modular railsounds era, the volume potentiometer was in the analog output section and was ALWAYS specified to be an audio taper pot. In the more recent era, the pot was moved into the digital part of the circuit to enable master volume from the CAB remote (in addition to blend volume). In this case, a linear taper pot is specified and the taper is compensated for in software.

It is possible that a particular engine might have the wrong taper pot, or that a pot might be defective. But I assure you, we know the difference between these component types and endeavor to provide a satisfactory knob-turning experience.

That's good to know Rudy, I've run across a number of them that clearly had a linear taper pot, so I made an "assumption".

Both tenders are from the late '90s-early 2000s, so I'm guessing they have the earlier version of the "pots" (?).

I had both apart earlier today; sprayed them with contact cleaner, with no change. As I say, not a big deal, as I'm not really into (literally) "bells and whistles"; was just curious... 

Mark in Oregon

I just took a dozen pots out of my parts box, they're from an assortment of Lionel and MTH locomotives.  I picked the ones that had the Lionel connectors as they're from the Lionel equipment.  All of these are from the modular Railsounds 5 or earlier era.  Of the 7 pots, only one was an audio taper, and the other six were linear taper pots.  Interestingly enough, all the MTH pots that were left were also linear taper pots.  They may be specified as audio taper, but one wonders what is actually getting into the locomotive.

Mark, there's an easy way to determine what you have.  Disconnect the pot, usually just pulling a connector.  Turn the power all the way CCW and connect an ohmmeter to the center lead and to the outside lead that reads zero ohms or close to zero ohms.

Turn the pot about 10% of the travel, normally about 270-300 degrees of travel.  Record the resistance.  Repeat until you get to full scale.

If the numbers progress up fairly steady, it's a linear taper pot.  If the first few are bunched together, it's an audio taper pot.  I'm curious as to what you actually have.