This structure was originally a 41.6kV KPF rack for a branch line that served a sub about a mile north which put out a single 7200V circuit for a small town another half-mile north. When the line was upped to 69kV, the expense of rebuilding the tap and sub wasn't worth it (given that the town in question is essentially a ghost town now). So, pull the KPFs, run a few jumpers, and viola'! The 41.6kV branch becomes a 7200V single phase line.