Update: Thanks to readers, corrected on the actual use of this right-of-way; it was a railroad line.
Disclaimer: Yes, I know this is a horrible photograph.
Yes, Ladue once had mass transit passing through it, as this right-of-way, just off of Litzsinger Road demonstrates. Here is a picture of the track in use at the Post website. Looking at old streetcar maps, the line that passed through Ladue had an indeterminate ending point. According to a family friend who lives in Ladue off of McKnight, the streetcar line never did very well. There actually is still a small, ornate pavillion at the entrance to his subdivision where the streetcar stopped. It’s still hard to believe sometimes that mass transit, streetcars in particular, were often times the domain of the wealthy.