Wiring a sound board help needed

If you do not have the answer yet, a picture of the board may help. AC voltage has no polarity. I would guess if one plug has diodes near it, that would be the power input.

Larry

AC may not have polarity, but since this is a conventional locomotive, the polarity of the whistle command comes into play.  Most electronic boards want the whistle offset to be positive on the center rail, the bell responds to the negative offset.

How about a picture of the top of the board with sufficient resolution to see the parts and any visible numbers?

Many Lionel Boards have marks near the connectors that identify there use.  Not all, but it may be worth examining closely.  Once you get the AC versus speaker you can test the board.  If the whistle button sounds the bell, just reverse the AC leads and you will be good to go.   G

Here is a photo of the board in question. Besides the speaker, what else do I need?

I do have the wire connectors for the board.

Based on the locations of the connectors, here's my "best guess" as to the connections.  You shouldn't need anything but the speaker, it doesn't appear that there is any volume control capability.

I'm making the assumption that those two black surface mount components next to the power connector are diodes, but the picture isn't of sufficient resolution to read what's on the chips.

Hopefully, someone has an example of one of these in a product, I didn't find it on a search.

I'll bet Boxcar Bill has seen this board and knows which connector is power and speaker for sure.