A Google search did not yield much. Pioneer was acquired by Patriot Rail, so it may have gone the way of the Dodo. I did find a newsletter from early 2022: chrome-extension://efaidnbmnnnibpcajpcglclefindmkaj/https://pioneerlines.com/wp-content/upl ... 202206.pdf
It was first published by a gentleman in South Carolina. At some point, he either retired or passed away. Pioneer Lines then took over publishing the magazine for a while. I am not sure how long that lasted.
Jeff