The SciencesConcrete Viaducts on the Pennsylvania RailroadReplacing Insecure Wooden Trestles With a Substantial Road BedBy Day Allen Willey on January 9, 1915AdvertisementABOUT THE AUTHOR(S)Recent Articles by Day Allen WilleyReclaiming the Everglades of FloridaSnag Boats on Flood RiversComfort for Workers in Washington's Government Buildings