Well, last night I fooled around with the sound board in question. Using deductive reasoning, I determined which wires to hook up to the power, 9 volt battery, and which ones to the speaker. The deductive reasoning boiled down to looking really closely at the board and finding that of the five wires sticking out of one end, 3 red, 1 black and 1 green, two of red wires were marked on the circuit board + and -. Then looking even closer I found two green wires near the center and to one side, marked B and D. One of these wires was cut off so close that I nearly missed seeing it.
After powering up the whistle sounds and chugging starts. The whistle only sounds at start up. The chugging rate is controlled by one of two potentiometers,. The second potentiometer controls the volume. I was unable to figure out what the remaining wires were for. These would be the two reddish wires on the left in the first photo that are twisted together and look as though they return to the board, but in fact were cut. The black and green wires adjacent to the three red wires are still a mystery.
If anyone wants to experiment with the board they are welcome to it, along with a speaker. The only request is that postage be paid.