Eastern Railroad Depot, East Boston, 1852 (BPL).
The second Eastern Railroad Depot on Causeway street is at the far right in this cropped photograph. The Boston and Lowell depot is the larger building in the foreground.
Eastern Railroad Depot, Causeway street (second from left, beside the larger Boston and Lowell depot) 1883.
Unfortunately, I have yet to find a photograph of the original Eastern Railroad Depot in East Boston. The Eastern, like all the early railroads, was built out of multiple mergers. While competing with the Boston and Maine as a Boston to Portland line, the Eastern followed the coast closer than the B&M line did. The Eastern was founded in 1836, running north through Salem, Lynn and Newburyport. The same track is still used by the MBTA for its Newburyport/Rockport line.
Unlike the Boston and Maine, the Eastern did not originally have a depot in Boston proper. The first depot, shown in the top map, was in East Boston, on a wharf beside that of the Cunard line. From there, ferries would carry passengers across to Boston. Right around the time that map was made (1852), the Eastern laid a connector line in to Boston, and built the Causeway street depot. Around 1884, the Eastern was leased by the Boston and Maine, and ceased to exist as an independent company.
In 1893, the new North Station (also called Union Station) would open on Causeway street, replacing the four older stations shown on the last map above. That depot would in turn be replaced by a new North Station, which would later be replaced by the existing facility. The two earlier North Stations will be the subject of another entry.