You are in the CarrTracks website Picture Gallery.
Tower 19 was built in 1903 to control movements at the crossing of the MKT Dallas to Hillsboro line and the Santa Fe Dallas to Cleburne line. The Santa Fe upgraded Tower 19 from a 24 lever mechanical interlocking plant to a GRS 82 lever electric plant in 1917. Traffic increased in 1924 when T&P traffic shifted to the belt line around southern Dallas. The GRS electric interlocker machine was expanded to 112 levers in 1932 when it took over the functions of Tower 10. Tower 10 controlled the crossing of the Houston and Texas Central with the Santa Fe northeast of Tower 19. A Union Switch and Signal CTC Board was installed in 1952 to control the Santa Fe single track line from Hale (Oak Cliff) down the hill to the junction at the tower. In 1990 the Santa Fe sold its downtown yard and trackage up the hill to near Hale to the Dallas Rapid Transit system. Service at the tower ended in 1993 and the tower was moved to Fair Park in 1996.
These pictures were taken around 1990 and are at the Library of Congress website. I have some video of the operator lining Amtrak through the plant in late 1992. These pictures should give you a good idea of what the inside of the tower looked like before it was retired.