This 138kV highline has been in service in San Antonio for many of years at least prior to the 60's and it runs down Austin Hwy on the Northeast side of town. I had an uncle that use to live on Austin Hwy. and we would go visit on weekends and I would wonder why the power company used substation insulators that are cap and pin type designed for buss tube support in substations to hold up the conductors on this long running highline! Never did find an engineer at the power company that knew why they did it and I worked for that company for 10 years as a lineman and we never had a issue with that heavy loaded transmission line, guess somebody had a good idea at the time!