Dual 230 kV circuit towers.

Before you say anything, the tower in the foreground (closest to me) has fiberglass brackets, so because fiberglass is an insulator, (Though not as good of an insulator as porcelain or polymer) it halves the amount of disc insulators needed if it was connected to straight metal.

As you see in the background the tower is much bigger and has more disc insulators used because the brackets are metal.

I think they did this for the regular suspension straight towers because it is cheaper. For one, fiberglass is cheaper then metal, and since fiberglass is an insulator, you need only half as many disc insulators. But the overall cost is that these don't last as long as if you used the bigger towers.

The tower here is the last "cheap" tower heading east and east of here on this dual-circuit the straight suspension towers are all metal and have 16 disc insulators instead of 8. And are much bigger.

Though these towers are still old, they still decided to be cheaper here, but at least they still used lattice towers instead of wooden poles.