I don't know about Morse Code on Main Street, but perhaps your'e thinking of the telegraph sound coming from the New Orleans Square train station at Disneyland. In that instance, the telegraph is tapping out Walt Disney's speech at the opening ceremony. ("To all who come to this happy place, welcome." etc)
As for SSE, I believe it's still tapping out the message about the golden spike and the transcontinental railroad. (The two guys there at the desk actually say the words as they transcribe the message). The Amelia Earhart info comes from the newscaster inside the radio booth on the opposite side of the ride track.
-Rob