Rick Porter has kindly contributed a package of Hopewell railroad research material that clarifies the construction of the Hopewell Railroad Station and the path of the Mercer & Somerset railroad tracks through Hopewell Borough.

The date of the construction of the Hopewell station is surprisingly inconsistent in various sources. We now have extracts from the Hopewell Herald detailing its construction during 1876, and showing it open for business in January 1877.
In addition, the architect / builder of the station is listed as unknown in the National Register nomination. The Hopewell Herald extracts show the contractors as “Messrs. [John] McPherson and [Daniel A.] Clarkson of Pennington,” who also received the contact for the Pennington Station. (Clarkson is credited as the builder in the Pennington National Register application, which reports the station was completed in 1882.)
McPherson and Clarkson also are shown in Pennington in the 1875 Everts & Stewart map, with their residences shown between the two tracks, and the 1880 U. S. Census records recording McPherson as “Architect” and Clarkson as “Dealer in Coal.”
The exact path of the Mercer & Somerset tracks through Hopewell Borough also is unclear, as it is described variously as running along Model Avenue, or shown in the 1875 Everts and Stewart map as above Model, with the then station between it and the new D&BB tracks just to the north. We now have Mercer County deeds from 1874 and 1876 for the purchase of the D&BB right of way through properties in Hopewell Borough that includes maps showing the D&BB and M&S lines.
So it appears that the right of way for the M&S ran down below the current Model Avenue, extending through the current Cook Place.
For more on our local railroad stations, see the earlier post on Railroad Stations in the National Register of Historic Places, with the National Register nomination documents for the Hopewell and Pennington stations, plus the preservation plan for the Hopewell railroad station.