We contacted the Maine Historical Society in Portland for their opinion about the striped poles and received the following reply from Scott T. Hanson, preservation compliance coordinator: My first thought when I looked at the photo you sent was that it reminded me of a railroad signal and was probably related to the trolleys. The first view above seems to support that. I think they maybe indicating to passengers where the trolley will stop, or to let the trolley driver know when he is clear of the switch where the passing track ends. The two posts might indicate where to stop with a one car “train” or a two-car “train”. So, I don’t know the answer, but I strongly suspect it is a signal related to the operation of the trolleys.