While browsing through Youtube, just now, I came across this video someone shot from the rear car of a train crossing the Hellcat Bridge. I'm always so impressed with the infrastructure the Pennsylvania railroad built. Not only was it built to last but there was a thought process that went into it's design. Everything from the bridge itself to the catenary supporting masts was well thought out. Not only in terms of structural design but also in architectural statements.
If you watch the entire film, keep a lookout for the speed change at about 3:00 minutes into the video.