Three Brooklyn Race Tracks in 1913: What Happened to Kings Highway?

In the map below, I brought in the 1913 Street Railway Map that shows interesting features besides the then running streetcar lines.  The former Brooklyn race tracks, the Gravesend, Brighton and Sheepshead Bay were still around according to the map, but mapped under different names.  Notice that the Gravesend Race Track near Gravesend Avenue (Mcdonald Avenue) had a different shape than what I posted earlier.  Perhaps the land was being developed.  I looked closely and on the 1913 grid, I did not see  Kings Highway which is the northern boundary of the former race track.  I then brought in the modern street grid and it shows the position were it should be, eventhough I am slightly off due to georeferencing problems.  The Nostrand Avenue Trolley, which according to the 1913 map is slightly off from my grid, but it shows that it ends at Avenue T before it reaches the Coney Island Jockey Club ( formerly the Sheepshead Bay Race Track?).  It is possible that the 1913 map has some errors in it if it is missing Kings Highway.  The trackage on Nostrand Avenue may have been single tracked between Kings Highway and Avenue T at this time and Nostrand Avenue ended before reaching the race track. To be continued.   The picture below the map comes from a picture website called http://www.brooklynpix.com.  This 1915 picture shows the right of way of the Culver Line on McDonald (then Gravesend Avenue) facing north from Avenue T.  If you look to the right, you can make out the extensive race track buildings that were still in existence at that time and probably little land development took place by that time.  The present day steel elevated did not open to 1919.