Track Elevation at Dayton, Ohio

Does anyone know when the Pennsylvania RR elevated their tracks in Dayton, Ohio. I think it was maybe pre 1950. It was a pretty big project as they built around 7 bridges over city streets. It shows up good on Google Earth, but, I can't find a date. I think my father worked on this. He worked for a Bates & Rogers Construction Corporation and they built this section. They just don't say when they built it.

See this photo http://www.daytonhistorybooks.com/album ... 652.htm..I believe it was the last project in the flood plan of the Miami Conservancy District.All the rivers entering Dayton were Dry Dammed ,Miami,Mad,Stillwater,and Twin Creek up stream.The Miami and Erie Canal was back filled.The New York Central and Erie Railroads were realinged because of the Huffman Dam.Dayton was completly cut off from rail freight in the 1913 flood.The only line not effected was the Cincinnati Lebanon and Northern which was east of Clement Hill and ran south to Cincinnati on a lateral moriane.It was proposed that the elevation of the Dayton Union Railway,(B&O,PRR,NYC,Erie)would make them less likly to be flooded and eliminate street grade crossings.Sorry he link will not work .The last passenger train(B&O) at steet level Sept.1 1931