It's a K-Line/K-Line by Lionel steam sound board for the A5 switcher. Can't find any documentation on it, but I suspect 2 connections are for the speaker, 2 for power, and 1 for a 'cherry switch".
It would be helpful if you could post a picture of the top side that clearly shows any lettering or markings, e.g., +/-, on the board. Lionel has a pic in their parts listing, but the lettering is not readable.
