This company likes to build substations in this style - in this case, the incoming power line is 22kV (making this company one of the very last in the USA to still be using this early system voltage) and the line heading out is 2400V delta. The three multiparts on the 2400V lead are M-2610Bs and likely what the company used on the 22kV system before it was rebuilt using small posts. A couple modern voltage regulators sit inside the fence waiting to replace the trusty old units currently in place.