Map of Boston's central subway (plus Lechmere Viaduct), showing portals used over time, with opening and closing times.  See further corrections are related image <a href="//commons.wikimedia.org/wiki/File:Tremont_Street_Subway.jpg" title="File:Tremont Street Subway.jpg">File:Tremont_Street_Subway.jpg</a>.
User:SPUI and User:Dicklyon
Own work based on: <a href="//commons.wikimedia.org/wiki/File:Tremont_Street_Subway.jpg" title="File:Tremont Street Subway.jpg">Tremont Street Subway.jpg</a>