By trial and error, I discovered by pressing F8 three separate times, it not only mutes the loco, but shuts it down too.

I'm sorry that I didn't mention HO scale.  I'll try using a small flat bladed screwdriver; it can't hurt.  There just didn't seem to be much clearance between the shell and the floor assembly.  SINCE I MADE THIS POSTING, I discovered the previous owner had glued the floor in.  After careful use with an x-acto knife, I was able to remove the floor to add weights.

Tried F8, but it seems to activate another sound function.  Both of my other sound equipped locos use F8 as the mute function.  Thanks anyway.

I bought a Bachmann diesel locomative recently.  The seller told me he had installed an MRC sound decoder in it.  When I got home, I put it on my program track to read the address that had been assigned to it.  I then placed it on the main, called up the address on my throttle, and it came to life.  However, I could not find which F function mutes the sound.  I went to MRC's website, but failed to find the information that I was seeking.  I'm sorry to say that I don't know what MRC decoder model it is, but any help would be appreciated.

At a train show I recently purchased a used Bachmann  McKinnley Explorer Set to include the locomotive and dome cars.  I would like to add weight to the cars to bring them up to NMRA standards, but want to avoid destroying them while opening them up.  Any hints would be greatly appreciated. 

It's in a Bachmann box, and doesn't appear to be that old.  I've been modeling since the late 70's, and don't remember this set from that time period.

My wife recently bought a Orient Express Train Set at an estate sale.  I would like to convert the loco to DCC, but the box didn't have an exploded view of the locomotive.  Is there an exploded view available online, or can someone give me a hint as to how to take the locomotive apart safely.