In 1967 young people were told that plastics were the future and the future did not disappoint. Today the world is made out of plastic, carbon fibre, corrosion resistant lightweight alloys, high strength concrete and LEDs. This technology has generally converted our world from one where stuff is expensive and people are cheap, to exactly the opposite. I could go on and on about the many economic ramifications of this, but in essence "things" went from being crafted and artisan, to being so invisible that they might as well not matter. Back in the day the Pennsylvania Railroad was the largest private employer in North America with over 300,000 employees, roughly the same as WalMart. This vast army of workers was needed to polish, paint, lubricate and generally maintain all of the expensive, labor intensive technology that allowed humans to move at speeds faster than brisk walk. Replacing the materials of old was part and parcel to being able to replace the workers that cared for them, however as we charge into the middle of the 21st century some of these materials have soldiered on in the service of railroad signaling and, until their inevitable replacement, they provide a window into the pre-digital industrial age.
|CSX Washington Sub - South Orange Interlocking|
|CSX Philly Sub - MP 80 Auto Signal "Whitemarsh"|
|CSX Cumberland Sub - Paterson Creek interlocking|
Also used for bridges and track structure, wood was the plastic of its day. Light and easy to shape, it also has tensile strength allowing it to span distances in a way that stone or concrete cannot. Although it was excluded from most signal structures, wood was employed in pole lines to support the signaling and telegraph wires that carried little bits of voltage from one signal location to the next. Unlike steel, stuff can be easily attached to wood with nails or screws and, somewhat surprisingly, wooden poles can also last decades after being impregnated with petrochemical tars. However modern technology found other ways to eliminate the wooden pole lines by replacing the wires they carried with fiber optics or wireless signals.
|D&H 'QS" Interlocking, Mechanicville, NY|
|PRR 138kv Transmission Line near Martic Forge, PA|
|CP-MIDWAY - Port Road Branch|
|CP-SLOPE, Altoona, PA.|
|CSX Cumberland Sub - Magnolia, WV|
More expensive than its pole line cousin, optical glass collected the light from the low wattage signal bulbs and and protected it 1-2 miles down the track for approaching trains to see. Most color light signal lenses consisted of an inner colored glass filter assembly with an outer Fresnel lens that focused the beam. Today these have been replaced by high intensity LED's that often do not need a focusing lens, making do with a cheap clear plastic cover.
|CP-RADE, Radebaugh, PA|
|CP-TRAFF, Trafford, PA|
|CP-HAWSTONE, Lewistown, PA|
|PRR OVERBROOK tower.|
|CSX Cumberland Sub MP 130 Auto Signal "Drywall"|