High pitched sound from poles

Hi, There are new (phone/internet? Electricity?) pole toppers in the neighborhood (excuse my ignorance, I tried to research but couldn’t find the answer). They make an extremely high pitched constant whirring sound that we can even hear inside with the windows down. There is one at Sheridan and Jackson and one at Sheridan and Wellesley. What are they, and is the noise an additional price we pay for phone/internet/electricity etc. now? Liz Buchanan