Ah, OK then.
Very old B'mann locos are sometimes termed "growlers".
The source of the noise is poor alignment throughout the drive train and/or cracked gears.
Some associate the sound to a coffee grinder.

You used the words "Very old".

So let's say, for the sake of argument, 15+ years old.
At that time B'mann locos were notorious for cracked gears.

This is the stigma, to this day, that haunts Bachmann N scale locos.
It appears to have been addressed.

I have Spectrum locos, both steam and diesel, that do not exhibit this problem. My Spectrum Dash 8-40C's were growlers, my Dash 8-40CW's were not.
All my Spectrum purchases are from 2004 or later.

FWIW I also own the new split frame Steam 0-6-0, 2-6-2, and 4-8-4 versions and they are all quiet and smooth. My earlier versions of these same locos (solid frame - pre '95) all suffered from cracked gears.

Check your gears.

bobv

What scale is this locomotive?

If you can figure out what's causing it your half way there.

You don't state the manufacturer so try some of these;
Remove the shell and run the chassis on the track.
Check for slop in the drive train, from the motor shaft throughout the trucks.
Check for worn motor shaft bushings. 
Check for something loose or vibrating.
Check that the motor is tight and properly seated.
Check that everything is aligned properly and that nothing is binding.
Check for proper lubrication.
Check the fit of the shell. The shell may be amplifying the noise.

See if you can isolate the source, and report back.

Fomoco,

The standard line from Bachmann offers 2 locos with smoke units, the 0-6-0 and the 2-6-0. I do not believe they are DCC equiped. I do beleive they can be converted to DCC fairly easy.

The standard line is not on par with their Spectrum line.

If you desire sound coming directly from the loco/tender this will require a DCC sound decoder and a speaker.
There are stationary sound units produced that fit under, or on, the table. Although the sound cannot travel with the loco it's the only alternative I am aware of.

As previously stated the Spectrum line doesn't offer both from the factory.
Smoke units can be added as Stephen replied. If you have the time and abilities to add one (not too awfully hard to do) that may be your best bet. Shops can be found to do this for you if you don't.

Another manufacturer may have both smoke and sound.

Enjoy the hobby in anyway you want.
Pay no attention to those who think they know what YOU want and what YOU need.

It's good to hear you are getting your son involved early.

Good Luck.

Yes, to be fair, what Gene stated in this first sentence is correct.
Bachmann does not currently produce Spectrum Steam locomotives that have smoke units in HO scale.

Quote[Do you really want me to answer your questions? /quote]

Yes, I do Gene.

Please quote and reply from the Original Posters four sentences.

I am anxiously awaiting your reply.

How is it that you know what someone else wants?

QuotePosted by: fomocof250d  Posted on: February 09, 2009, 05:10:03 PM 
Insert Quote 
I am looking for an HO steam locomotive. I've been searching this site and looking but which locomotive has sound and smoke? I'm looking for a higher end like the spectrums. Is there a sure way to tell from this site?

The OP states this is what he desires, and asks for help finding such.

QuotePosted by: SteamGene  Posted on: February 09, 2009, 05:25:45 PM 
Insert Quote 
Spectrums do not give smoke.  You do not want smoke.  You may think you do, but you don't unless this is a temporary layout for grandchildren. 
For Spectrum with sound, look for "DCC with Sound on Board" or something very similar.  "DCC On Board" is not what you want nor is "DCC Ready." 
Do you have any idea what kind of steam locomotive you want from what railroad?
Gene

Please SteamGene; tell me and the other forumites here how it is you know what the OP wants?
Contrary to what you might believe, there is more than YOUR way to enjoy the hobby.
Please explain this "special gift" you have in that you "know" what others want.

QuotePosted by: SteamGene  Posted on: February 09, 2009, 05:25:45 PM 
Insert Quote 
Spectrums do not give smoke.  You do not want smoke.  You may think you do, but you don't unless this is a temporary layout for grandchildren. 
For Spectrum with sound, look for "DCC with Sound on Board" or something very similar.  "DCC On Board" is not what you want nor is "DCC Ready." 
Do you have any idea what kind of steam locomotive you want from what railroad?
Gene

Why ask the question Gene? Don't you know what the OP "needs"?
In your infinite wisdom you already know the answers.
You're a legend in your own mind, and nobody is as smart as you think you are.

Glad it was such a quick easy fix.
In my last post I suggested powering the turnouts you are manually activating.
This would have shown you that when utilizing the power selector box, the power activated coils will hold the points in place against the rails.

To try this, while using live AC power to your switch boxes, remove the loco from the tracks, and attempt to move the points to the opposite direction with light finger pressure. You will find the points spring back to the proper position.
Switch points perform better with a bit of filing, to sharpen, to get them to lay as tight as possible against the rail.

As an aside, I have bought a new B'mann turnout where the pinion gear was assembled "one tooth off" to being correct. This causes excessive pressure against one rail while putting less then adequate pressure against the other rail.
If the points are not solidly contacting either rail, in the desired position, you need to check first the position of the pinion gear in relationship to the selector rack gear, and second the spring coming straight (parallel) out of the spring holder.
I am glad you have a quick fix, as my picture posting skills to this site seem to be severely limited.

Bachmann does NOT use consistent wiring methods, or consistent color coding in their products.
If you open the turnout up, pay strict attention to this, least you will have a short.

Good Luck

Just for kicks and grins, try to power your other turnouts and see if you still have a problem with them.
After doing that, if you still are having problems, report back and I will send you a picture with instructions detailing how to set the spring tension internally.

Welcome back to the hobby.
New track is not clean. Clean the tracks by wiping with lint free cloth and isopropyl alcohol. Then clean the wheels of your locomotive and rolling stock using a Q-tip and the alcohol.
After that, if you still have the problem on the re-railer, check to see if the wheel flanges are bottoming out on the flange way and "lifting" the loco.
Random power surges and screeching sound to me like dry motor shaft bushings may be the culprit. A small drop on each with plastic compatible light oil should quiet them.

"would you need a power feed (terminal track) at each heel of the switch tracks???"

No, it's not necessary, but maybe helpful depending on the size of your layout.

The terminal track does not have to connect directly to the turnout, it just needs to be somewhere along mainline before the turnout. (i.e. at the bottom of the "Y".)

"also what does "power routing" mean?"

Power routing means that power will only flow in the direction of the switch points not to both legs of the turnout. Power will only flow to one or the other, either along the main or to the siding/spur, not both at the same time.

Maybe this thread can help;

http://www.bachmanntrains.com/home-usa/board/index.php/topic,967.0.html

Please draw a track plan of what you have, highlighting the position of your turnouts and the power feed and post it here as either a gif. or a jpg. or similar.
B'mann EZ track turnouts (switch tracks) are power routing.

As TC says you will get a lot of opinions on this.
Here is mine;

Note a higher gauge number is smaller wire (diameter) while lower number denotes a larger diameter wire.

For feeder wires nothing smaller than 20 gauge.
I like 18 gauge cut into one foot lengths and soldered to the bus wire, Spaced about every 6 feet.
On my next layout I will solder one feeder to each piece of flex track. Overkill? Yeah, a little bit, but I will no longer rely on rail joiners to carry power from one section to the next.
Current layout is all sectional tracks.

For Bus wires, I like 14 gauge. 16 gauge would work but I have a ton of free 14.

I prefer solid to stranded wire for the simple reason, whenever I strip stranded wire, I always manage to accidently cut off a few strands in the process.

If you want to get technical you can research Ohm's Law to figure it all out.
You don't need an Electrical Engineering degree to enjoy Model Railroading, but a very basic understanding of Ohm's law sure comes in handy, as does a Multimeter.
While using DC, small fluctuations may seem negligible, using DCC that may not be the case. DCC is much less forgiving.

http://www.physics.uoguelph.ca/tutorials/ohm/Q.ohm.intro.html

Ernie,
From some of your previous posts you "claim" to be an "older gentleman" (55+) I can only give you the benefit of the doubt.

However from some of your previous posts, I question that claim.

That said:
Surely, if in fact, you claim your are somewhat advanced in age (40+) you are familiar with the term "Return receipt".
My dilemma is that whenever sending "monies" through the postal system (Cash, Checks, or Money Orders) you would not request a return receipt.

Something smells like fish to me.
You post on a forum that you "sent it".
What proof do you have?

Hopefully (if the seller never received the money order) the seller will give you a negative feedback as some type of scam artist.
I would.

Bid on my item and don't pay.
I'd blast you.

You come here asking for help... we only know one side (allegedly) of the story.

No sympathy from here.
Suck it up

"New" track is not clean.
Wipe it with alcohol on a rag, you will see.

Un - plug it from the wall, just as any small appliance.
If it's pluged into a power strip, switch the power switch off.