Thanks for the reply. Much appreciated. 1N3311B (Zener) and 1N1186RA (Normal diode) have the same polarity. Both were correctly installed. When installed in reverse (or the center rail and outer rail leads switched to simulate the same polarity reversal of a diode) the Lionel Sound Activation Button will activate the bell from the electronic sound car and not the electronic whistle in the electronic sound car . And only the whistle from the old tender will sound from the handle on the KW, but will ALSO ring the bell at the same time. Then you have to hold down the sound activation button for two plus seconds to shut off the bell. Turn the handle on the transformer and the bell and (old) whistle sound simultaneously. That's the problem I was having with the 6A10 (see the first post) installed the way that article I followed incorrectly showed me how to install it (backwards). They also fried (two of them). Rob pointed that out earlier in this thread.
When the 40A barrel diodes are installed properly (as they are now) the whistle handle on the KW blows the whistle located in the sound car in position 1 and both whistles in position 2, and the 6-5906 button will only turn the bell on and off.
The drain on the center rail (since ALL center rail power MUST route through the sound activation button) is pronounced and others on train forums have reported this as well. One of the "solutions" was to substitute that exact Zener diode for the 1N1186RA. The controversy was whether the resistor was necessary (but not detrimental). So far the Zener has not prevented or reduced the power drain. I do like to run my trains at relatively low speed for realism. Maybe that's the problem.
Some recommended two buttons. Haven't tried that yet and don't know how to hook them up (series or parallel). I will take some measurements with a VOM to see if I can get any values that are helpful. But for now the Zener is exhibiting the same problem as the non-Zener in terms of center rail power loss.
John
