Jon
Landry Connecticut reports that notwithstanding modern technical
developments, the overwhelmingly dominant track form worldwide consists
of flat-bottom steel rails supported on timber or pre-stressed concrete
sleepers, which are themselves laid on crushed stone ballast.

Most
railroads with heavy traffic utilize continuously welded rails
supported by sleepers attached via base plates that spread the load. A
plastic or rubber pad is usually placed between the rail and the tie
plate where concrete sleepers are used. The rail is usually held down to
the sleeper with resilient fastenings, although cut spikes are widely
used in North American practice. For much of the 20th century, rail
track used softwood timber sleepers and jointed rails, and a
considerable extent of this track type remains on secondary and tertiary
routes. The rails were typically of flat bottom section fastened to the
sleepers with dog spikes through a flat tie plate in North America and
Australia, and typically of bullhead section carried in cast iron chairs
in British and Irish practice. The London, Midland and Scottish Railway
pioneered the conversion to flat-bottomed rail and the supposed
advantage of bullhead rail — that the rail could be turned over and
re-used when the top surface had become worn — turned out to be
unworkable in practice because the underside was usually ruined by
fretting from the chairs.

Jon
Landry CT observes that the time of sunset varies throughout the year,
and is determined by the viewer’s position on Earth, specified by
longitude and latitude, and elevation. Small daily changes and
noticeable semi-annual changes in the timing of sunsets are driven by
the axial tilt of Earth, daily rotation of the Earth, the planet’s
movement in its annual elliptical orbit around the Sun, and the Earth
and Moon’s paired revolutions around each other. During winter and
spring, the days get longer and sunsets occur later every day until the
day of the latest sunset, which occurs after the summer solstice. In the
Northern Hemisphere, the latest sunset occurs late in June or in early
July, but not on the summer solstice of June 21. This date depends on
the viewer’s latitude (connected with the Earth’s slower movement around
the aphelion around July 4). Likewise, the earliest sunset does not
occur on the winter solstice, but rather about two weeks earlier, again
depending on the viewer’s latitude. In the Northern Hemisphere, it
occurs in early December or late November (influenced by the Earth’s
faster movement near its perihelion, which occurs around January 3).

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