Concrete arches in Northeastern Pennsylvania

[Pete from Boston]

Is it me, or are large concrete arch bridges more common in Northeast Pennsylvania than in most places?  I was in Scranton earlier this year and noticed they seemed common, and the DL&W Delaware River bridge and the Fort Jenkins Bridge in Pittston also follow this model.

Is it a time period thing, locally available material, or am I just imagining this trend?

[sparker]

Is it me, or are large concrete arch bridges more common in Northeast Pennsylvania than in most places?  I was in Scranton earlier this year and noticed they seemed common, and the DL&W Delaware River bridge and the Fort Jenkins Bridge in Pittston also follow this model.

Is it a time period thing, locally available material, or am I just imagining this trend?

It is prevalent in NE PA, particularly with railroads, because the major cargo carried by RR's in that area was anthracite coal -- and heavy coal trains really don't want to go up and down hills.  So the railroads built long heavy multi-arch bridges (the Tunkhannock Viaduct northwest of Scranton on the old DL&W line is the largest of these) that spanned whole valleys in order to maintain a consistent low gradient!  The concept migrated, on a smaller scale of course, to roadways in the area, particularly those serving as truck corridors.  The design also showed up on other RR bridges across the Susquehanna & Delaware Rivers and their various branches, since coal and other heavy cargo was part & parcel of commerce in that part of the country (and remains so to date).