For some modeling ideas, I have attached THE FIRST TWO photos of an early Switch Tower on an IRT EL Line - the New Lots Line EL - this older era style of Switch Tower House somewhat resembles the style and look of the O-Scale Plasticville Switch Tower House kit, readily available in the hobby. These "small" towers were not only found on 1904-1920 era built NY EL Lines, but also on the very oldest 1880's built Brooklyn BRT-BMT and Manhattan IRT EL Lines.
ALSO shown are the SIX FOLLOWING photos of 3 of those O-Scale Plasticville Tower House, somewhat detail-up-scaled and repainted by me, as shown in various locations along the EL tracks, on my O-Scale NYC EL Layout. Three different tower "location applications" are used:
--One Tower is located between two tracks;
--One Tower is located at end of station platform;
--One Tower is located along side of the main EL structure.
These are 3 common locations found along most EL lines in the era of having numerous working, in use, towerhouses.
Regards - Joe F