Okay, I found it in the February '06 issue of CTT. Here’s the direct quote:
[i]"… Senco Sound Co. of Pittsburgh, Pa. produced the tender. To the best of our knowledge, it was the only train item Senco made. Available for seperate sale, the tender was intended for use with Lionel locomotives. The unit was an early attempt at providing rolling-steam sound effects for tinplate railroads - hence the pickup rollers.
I’m not sure how it worked exactly, but the tender had a smaller speaker inside and came with an in-line “transmitter” and a 10-inch record that played on 78-rpm turntables.
The concept was ahead of its time and the mechanism somewhat cumbersome, so sales were slow, and the tender was on the market for a relatively short time.
Our research came up empty as to the date of manufacture, but our best collective guess would be the early 1950s…"[/i]
There was an update in the July '06 issue of CTT:
[i]"Ron Rupp of Canton, Ohio, was kind enough to send us all the information available on the Senco Sound tenders… Our estimated time frame was a bit off - the literature mentions 1947 - but the overall concept was close.
The Senco system provided pre-recorded, real-railroad sound effects that rolled behind the locomotive as it traversed an O gauge pike. Without question, this was the first attempt to add realistic sound effects to a toy train layout, which we all take for granted today. Two different tenders were offered, one for 3-rail AC operation and another for 2-rail DC operation.
The Senco line included a Pennsylvania Railroad-style die-cast tender, with a speaker and condenser pack inside; a “mixer” box; a 10-inch, 78-RPM sound effects record; and even a small turntable/phonograph, if the customer didn’t already have one. The components could be purchased seperately as needed or as a complete package for $54.45, quite a lot of money in those days.
Apparently, the electronic output of the phonog