Owing to the importance of the South Side as a point for the delivery of freight, a reasonably direct and easy approach from there to the new tunnel seems desirable. Freight to be teamed to the South Hills District seems likely to originate either near the Smithfield Street bridge, or east of South Seventeenth Street. From the former point, it is almost out of the question to get an approach of easy gradient to the mouth of the tunnel, on account of the lack of distance; but it must be remembered that the inclines will still be available, greatly relieved by the new tunnel from their present congestion, and further that freight for the South Hills could easily be shipped to points from which access to the new tunnel would be easy and direct. From the latter point, the connection can be secured by climbing over the railroad on a viaduct, probably along South Twelfth Street, and thence following the hillside westward on a more or less uniform gradient to the mouth of the tunnel. An examination of the hillside below the Brownsville Road indicates that such a street, though somewhat costly, is not in the least impracticable. It might be best to construct it with a minimum of cutting by the use of a sidehill viaduct of reinforced concrete.
With the modifications above suggested the plan proposed by the residents of the South Hills, for a bridge and tunnel to the South Hills District, is eminently desirable. It is, therefore, urgently recommended as the best method of securing an adequate main thoroughfare artery to this region.
OUTLYING THOROUGHFARE IMPROVEMENTS
The following recommendations are in no sense the result of an exhaustive study of the main thoroughfare system of the Pittsburgh District. They comprise only the most desirable improvements noted during a general study of the outlying branches and connections of those thoroughfares which concentrate upon the down town district. The fact that a study undertaken with such a point of view has led so far afield that it has compelled the investigation of existing and probable connections so remote as some of those noted below, is, in itself, evidence of the complexity of the highway problem, and of the fact that it cannot be dealt with locally, in a piecemeal manner, without great sacrifice of opportunity.
The improvements are designated in the following text by numbers which correspond with those on the accompanying folded map of the Pittsburgh District.[11]
1. Sixteenth Street Bridge.—The first thoroughfare branch of the Penn Avenue artery is the Sixteenth Street bridge. Because of its physical unfitness, and because it is, at present, an unreasonable interference to navigation, it must soon be rebuilt.[12]
At the time of reconstruction, the railroad grade crossing on each approach should be eliminated, probably by carrying the street over the tracks. At the southern end, the grades make such a change very simple. At the northern end, the separation of grades will be facilitated if the tracks of the Pittsburgh and Western Division of the Pennsylvania Railroad can be lowered a few feet. No physical objection to such a change of track grade is apparent.
Diagram No. 1. Thirty-third Street improvement. Profile of Liberty Avenue