ZW whistle blowing issue

One solution is to roll your own.  I made this one from junk box parts years ago for a friend.  He later didn't need it and gave it back.  It's handy for bench tests, and has both whistle and bell controls.

@gunrunnerjohn, your design will drop power too as it doesn't provide the customary 5V boost that the classic ZW (and most classic transformers) have, and will still result in the effect of slowing the train due to the additional air whistle motor engagement.

@Larry Mullen, here is some very helpful information on how these classic whistle controls operate. 

The classic Lionel transformers and their whistle/horn activation controls have 3 positions:

Off - No whistle
Pickup- High DC offset just enough initiate the command
Hold - Minimal DC offset to hold the whistle command active and an additional +5V Boost to for older air whistles

The modern electronics generally only react to the Pickup and not the Hold position whereas the the older ones need to be engaged at the pickup and then immediately moved to the hold position to compensate for the additional load of the air whistle.

On the ZW, the Pickup position is selected by pushing the whistle lever partway, but not all the way to the stop.

This is documented in the Lionel literature:

Let us know if how this new user information works out.

Now, it may also not be user error - the rectifier disc in the whistle controls can age and deteriorate or contacts can get dirty. You can replace these rectifier discs or use diodes in their place. @Tranz4mr has a great webpage on servicing these ZWs and performing that work: http://www.tranz4mr.com/ZW_Whistle_Diodes.html

However, before doing surgery on the ZW, it fortunately has two independent whistle control circuits and so if you are using the A-U lever and whistle and experiencing the problem, temporarily swap the wires on the back and use D-U controls to see if the other whistle control circuitry is good.

Lastly, Olsen's kindly hosts the Lionel Service documents for the ZW:

ZW http://www.olsenstoy.com/searchcd31.htm?itm=671

ZW-R http://www.olsenstoy.com/searchcd31.htm?itm=672

The diode box drops the power all the time, but doesn't drop additional power when you activate the whistle or bell.  Unless you're maxed out on the throttle, the 3.0-3.5 volt power drop introduced by the whistle/bell box is not significant.

Thanks, guys.  @gunrunnerjohn / @bmoran4 , would this work if I don't want to open up the ZW?  *This is a pic from a current ebay auction.

That is similar to the homemade box of diodes.

It doesn't provide the customary 5V boost preventing slowdowns when the air whistle is activated, and it also only brings in the rectifier when activated, causing further voltage drop.

@Larry Mullen, did you at least try the other whistle circuit on your ZW as mentioned before?

We won't be setting the trains up until November.  Just getting a jump start on issues that we had before.  But I will take his ZW home with me and maybe set up a test track and try both.

@Larry Mullen posted:

Have a 275 watt ZW that will only blow a tender's whistle if the power is dropped significantly.  Is there an easy work around for this?  - maybe a separate whistle control?

Asking for my dad.

Thank you.

Does it do this with only the tender on track or with a locomotive pulling it?

Sounds like maybe a new rectifier disc or solid state diode upgrade is in order.

I just put a new disc in a 1033. With only the tender on the track it would drop out at higher voltages. I had another tender within reach so put two on the track and it worked perfectly. I suspect it would be the same with a running locomotive on with it.

It pretty much does it when it's being pulled by the engine.  I did just purchase new diodes so we'll see!