Won't Stop Whistling - 2 Obscure Wires (Electronic to Mechanical?)

dirty track is a common cause.

Dirty track and/or dirty wheels will cause it. Clean all three rails and all wheels on the tender, even the center roller wheel.

I had a Williams True Blast 2 tender sound off with transformer that did not have a whistle button with it. I cleaned the track and wheels and the problem went away.

I am not that into electronics to explain why dirty track causes this problem but just know that is it a dirty track problem.

Lee Fritz

I did happen to clean both the tracks and the wheels (including the center rollers), but the problem hasn't gone away.

It doesn't seem to matter what transformer is giving it the power either.

Any ideas what the problem could be now?

I had the same problem with two (2) of the more current Lionel 400E's. I purchased the 'traditional' versions to avoid the electronics. Despite being traditional however - the whistles use an electronic relay board. That board is not very robust. They were repaired two times each by the service tech at the LHS before I drove them in to MTH. The whistle would stick after 1-2 minutes of running. You may have the same issue with yours despite being somewhat different manufacturing. If your unit does not use an electronic relay as described then the manual relay may have become magnetized and is sticking (or stuck in this case) wide open. There are ways to demagnetize it but I'm not clear on the process. I'm certain someone here on the forum is however. I guess the first step is identifying if you do in fact have an electronic (board) relay or traditional old school relay. Not sure if this helps - but it is fixable.

Sounds like the solid state whistle controller in the tender may have croaked.  It would help to have the actual product number to look at what exactly is in the tender.

Unfortunately, Lionel doesn't have parts diagrams for their Classics line products.

Here's a few images to see inside.

Honestly, it was a poor design choice - you have to bend the tabs in order to disassemble the thing since the whistle unit is literally wedged inside!

John,

After opening it up fully, I found it did have an electronic relay board.

This might be a transformer problem.  I had a new Williams diesel running at a low speed. Its horn went off automatically and continuously until I moved the throttle up on one of the channels and made it go faster.  Don't ask me why.  All I know is that it happened that way on many occasions until I just set the throttle on the speed where it would not go off.  The transformer is a TAC 2001 that I purchased at a train show real cheap, and I  like it otherwise.  

After popping up the tender, I noticed that there were two wires going to nothing. This very much confused me. I'm sure one of them leads to common ground.

Unfortunately, I cannot seem to find a very good wiring diagram for Lionel air whistles on the Internet.

Another thing I should ask, if the problem is the relay circuit board, is to change it out with a mechanical whistle relay, which I happen to have?

It's likely the triac that drives the whistle motor, it could be fixed...  Those are simple boards.

But are they reliable? Is there a way to do so? I'd rather fix the problem at home by myself rather than waiting weeks for someone else to do it.

They are generally pretty good.  I don't know that specific board, but I'd be looking at the package that drives the motor.  Hard to say more without seeing the component side of the board closer up.

I see a relay, give that a sharp rap with a screwdriver handle and see if it starts working.

That tactic didn't seem to work...

I had a similar problem a while back with my 259's whistle, turned out to be the electromagnet. The contact became magnetized and was sticking to the electromagnet, I placed a couple pieces of masking tape in between them and it solved the problem. Yours could be something completely different, but I figured it couldn't hurt to put my experience up here just in case

I'd measure the relay contacts with the power off and see if they're closed.  If not, then I suspect the relay driving circuitry is bad.  Personally, I'd probably take a stab at replacing the LM324 op-amp.

The cover on small relays can sometimes be removed. If you think you can, hold it by the cover, and don't pry against the board/traces. Once off, you can check its points.

What a tech is often hoping for with a photo is a dead on shot close enough to read the numbers from the larger components, and/or number groupings printed on the board. The last pic was close, but wires blocked some numbers. 

In all those shots, I couldn't tell...What are the other ends of the two "mystery wires" leading from? I.e., What are they still connected to?