One of four bridges and tunnels at Westminster Junction, this tunnel is the southwestern structure, and by far the longest of the four.
Built for a the St. Paul, Minneapolis & Manitoba (Great Northern) mainline to cross the Northern Pacific, the bridge currently carries a BNSF track over a BNSF track.
Built in 1885, this tunnel was built using a cut and cover method, which included excavating land, building a stone arch with a brick lining, and covering it to form a tunnel. A 70 foot gap exists, and the walls are reinforced using concrete beams. This was added in 1921, as coal smoke from locomotives seriously degraded the limestone at this point in the tunnel.
With only two tunnels officially numbered, this structure has been assigned the number 3 by the author. At one time, five total tunnels existed at Westminster Street. Today, four remain.
This tunnel connects to the northwestern bridge as well, as the track goes through a trench with a drainage structure.
Overall, the bridge appears to remain in great condition, and should continue to serve traffic for many years to come.
A sign at the junction indicates that these four tunnels were vital to the growth of the St. Paul railroad network. Before the construction of this two level junction, a major bottleneck existed.
The author has ranked this bridge as being moderately significant, due to the economic impact these four tunnels had on the City of St. Paul and the railroad companies that built them.
The photo above is an overview.