By the end of June 1930, some additional filling in of Columbia Island was all that was needed to finish the Arlington Memorial Bridge. But no construction had occurred on the Columbia Island great plaza, its monumental columns, or the two pylons as the CFA had still not approved a final design for these. Additionally, work on the western half of the Boundary Channel Bridge had come to a standstill. Tracks of the Rosslyn Branch of the Pennsylvania Railroad ran along the Virginia shoreline. In order to avoid an at-grade crossing with Memorial Drive, the CFA proposed in June 1927 that these tracks be lower by . Since that meant extending the Boundary Channel Bridge, new engineering studies of the bridge were needed. The Corps and CFA were still studying how to depress the Pennsylvania Railroad tracks three years later. Informal negotiations had, by the end of June 1930, come to an agreement that the line would be moved closer to the river, and that an underpass through the bridge (accommodating two side-by-side tracks) and the depressed tracks should be constructed first before the railroad took title to the new line. This would permit uninterrupted rail service. The Pennsylvania Railroad also agreed to cede the old right-of-way to the government once the new tracks and tunnel were operational. Otherwise, construction on the Boundary Channel Bridge was complete.