They are used for trains to ride on them
Rail saddles used in railway construction include base plate rail saddles, chair rail saddles, and pedestal rail saddles. These components are essential for securing and supporting rails on railway tracks.
Widths were set by each rail company, which meant that equipment could not be used on other rail lines. The railroads, together with the governments, established standard rail gauges.
The only purpose for copper that I have seen on railroad tracks is as a connector between rail ends for signal conductivity purposes
Trains that run on tracks.
Metal can expand slightly when heated by the sun, a small gap allows the rail to expand, that said modern rail tracks are welded and do not have these gaps.
Rail tracks
Rail Road Tracks
ruts
The national Rail journey tracks different trains on all of the tracks in the United States such as the Burlington Northern Santa Fe or Amtrak trains.
A rail bike kit typically includes essential components such as a frame, wheels, pedals, brakes, gears, and a seat. These components are necessary for assembling a functional rail bike that can be used for riding on railroad tracks.
Railroad tracks, rails, or rail bed.
Standard Gauge. 4ft 8"