http://agathe.gr/overview/the_site_before_excavation.html
The Site before Excavation The Agora lies on sloping ground northwest of the Acropolis, below and east of the extraordinarily well-preserved Doric temple of Hephaistos, popularly known as the “Theseion” ... The Stoa of Attalos (c) was cleared of debris by the Greek Archaeological Society in 1859/1862 and 1898/1902, the extension of the Athens/Piraeus railroad (d) cut through the northern part of the site in 1890/1, and other areas (e.g., e) were opened up by German and Greek archaeologists in 1896/7 and 1907/8. ... In addition, as well as sharing all the logistical problems inherent in any large-scale urban excavation, the Agora site must be one of the few where a street and a railway divides the area of the excavations.