It was initially believed that the top of the viaduct was composed of solid granite blocks (originally carrying a single track). After the track and ballast were removed from the structure, troughs were discovered recessed into the granite capstones. The 18" deep troughs ran the entire length of the viaduct and were spaced approximately 56" apart (standard railroad gauge). In some locations, the trough contained a solid piece of oak, including some abandoned spikes. It is believed the troughs held wooden sleepers for the original single track railroad. These loose materials were removed from the deck, and lean concrete was placed to fill the voids. Archival photographs of the sleepers were taken and their remnants will be turned over to the local historical commission. At the approaches to the viaduct, a series of granite walls were uncovered running perpendicular to the tracks. These walls were approximately 7' on center, and it was thought that they might have carried a timber approach structure. The locations of the walls conflicted with new abutments for the PPC beams, and they made it difficult to install sheet piling for the contractor's support of excavation system. The walls were left in place undisturbed beneath the new track structure. HDR, Inc. redesigned the abutments to minimize their depths, eliminate the conflicts and reduce the loading of the temporary support of excavation system.