A closeup image of the rail's date stamp at the northwest shore of the bridge
reveals "96 IIIIIII" that translates to a forging date of July 1896.
Records indicate B&O's Patuxent Branch was opened in the late 1880s. Why
would the rails be replaced within about 10 years? The possible answer is,
according to USGS maps, the spur originally separated from the main line on
the north side of the Little Patuxent River, then quickly crossed over it to
the south bank.
Perhaps the Little Patuxent bridge washed out in the 1890s, and rather than
rebuild it, the railroad decided to move the starting point of the spur from
the north bank to the south bank. This move instead necessitated a bridge
over the Hammond Branch, which is a smaller stream than the Little Patuxent.