today, most yards with fewer than about 20 tracks merely have a yard office.
Control towers would be used for hump yards or large flat yards. However, thru the magic of selective compression, your several tracks could represent a much larger yard, thusly the tower.
A charming Lehigh Valley RR tower is provided in the link and would be appropriate for a small operation:
That Lehigh Valley tower looks a bit like the Plasticville tower, perhaps a bit shorter and with a more complicated roof. A good start for a kit-bash perhaps?