D battery and Blowing the whistle

[stuartmit]

Did I once see a wiring scheme indicating that wiring a D battery with a push button would inject enough DC into the track to activate the whistle relay, and blow the whistle? If so it would be a way of providing extra whistle "initiantions" to your layout which might be fun for kids to young to begin to take the throttle. Did I  make this up?

[servoguy]

 You can use a D battery to activate the whistle or horn.  Wire the battery in series with the transformer.  You will need a switch to connect the battery into the circuit when you want the horn to blow.

 Bruce Baker

[stuartmit]

Do i want a sp dt momentary push buttom to divert the trock power through the battery, or simply wire one pole of the battery to the center rail, and the other pole through a spst push button to the running rail?

[cwburfle]

Lionel described the switch that they used in that whistle controller as being "snap action". It switched contacts very rapidly, before the e-unit had a chance to drop. If you use a standard switch, there is a good chance the e-unit will activate when you try to use it.
Those whistle controllers turn up from time to time for around $5.00.

All that said, I'd be interested to see Bob's thoughts on using a "D" cell in this manner. Some things that I have read indicate that running AC through a battery may cause it to rupture. Even it this was OK to do when Lionel came out with this control method, battery chemistry has changed.

[sir james I]

The D battery method works for the PW relays but I have never tried it on a circuit board. Note the battery gets warm very quickly so don't blow the whistle too long.

[lionelsoni]

I would advise against putting a dry cell in series with the transformer, since the full AC current powering the train will have to pass through the cell, which is far from what it is designed for.  Lionel has made add-on whistle controllers that don't use dry cells.  You can make your own if you want, using a few diodes and a switch.  Either way, you will lose a little voltage when you activate the whistle.  The transformers included an extra 5-volt winding that was switched in to compensate.

Even though Lionel did use a D cell in the 147, I am skeptical that this is a good thing to do.  Primary cells often don't react well to attempts to charge them.  Manufacturers tend to warn against leaking or rupture.  In this case, the cell is being charged and discharged 60 times per second at several amperes, which is a pretty high current for that size of cell.  Another consideration is that dry cells have changed in the decades since Lionel sold the 147.  There are some very different types now; so what may have worked then might not now.

Given all this, I hesitate to mention that there is a simple circuit that can produce either whistle or bell signals from a single cell with two snap-action SPDT switches.  Connect the common of one switch to the transformer terminal that would have been connected to the center rail and the common of the other switch to the center rail.  Connect the switches' normally-open terminals together.  Connect the switches' normally-closed terminals together.  Connect the cell between the normally-open wire and the normally-closed wire.