Matt BlazeSignal Bridge with Phase Break Indicators, Pennsylvania Railroad, Perryville, MD, 2010.
All the pixels, but look both ways first, at https://www.flickr.com/photos/mattblaze/4509479059
Steve1981Captured with a DSLR camera and an 85mm shifting lens (with a small amount of vertical shift).
This "Signal Bridge" is a fairly iconic example of the industrial design style used in the electrification of the Pennsylvania Railroad in the early 20th century (and largely still standing today). It supports the electrical catenary wires over the tracks as well as signals that indicate track conditions.
These particular signals, which are unusual, are used to warn oncoming trains of a temporary interruption in voltage between two track sections fed by different power substations, called a "phase break". There are only a handful of these in the system.
Infrastructure is heroic.
cynicalsecurity 
@mattblaze beautiful (from a train geek so a little biased)
nothingiseasy@mattblaze I found a great photo of a phase break signal lit up on the railroadsignals.us website.
@Robgbysea That looks like the one north of Temple in Philly.