[Music]
all aboard
one thing that's part of every train
journey are those rocks you see under
and alongside the track
what are those for anyway and how does
this bed of stones not fall apart under
the weight of a moving train plenty of
questions and I've got all the answers
you need how is track ballast made to
start with that bed of rocks has a name
it's called the track ballast it has a
very important job to do to trains
transport around 40% of the world's
cargo so they need a railroad that's in
good condition and built to exact
precision so you just can't throw a
bunch of rocks into a pile lay some rail
on it and call it a day the thickness of
the track ballast layer will often
depend on the conditions it's built in
the terrain of that area and how much or
what kind of traffic the railroad will
get but it's usually laid about ten
inches deep and then fill to the top of
the cross ties that's those wooden or
concrete slabs between the tracks that
hold them in place
if the ballast isn't deep enough the
track might sink can you use any rocks
for the ballast nope sorry if you take a
closer look at the gravel you'll notice
that there's not a single smooth stone
in it each Rock has sharp jagged edges
and that's not a coincidence if you use
round pebbles they'll slide down and the
ballast will spread out that's not good
since the main idea is to provide
support and solidarity to the track so
to prevent that giant mess from
happening the ballast is made from
crushed gravel which allows the sharp
edges to interlock with each other kind
of like a puzzle
also in sections of freshly laid ballast
speed limits are always lowered this
gives the rock some time to fully saddle
okay but what's the ballast for well now
you have an idea that this gravel
provides support for the railroad but
that's not all where roads are exposed
to a lot of conditions that easily wear
them down
heavy rains may cause flooding over them
vibrations can eventually destroy them
and stress from heat and friction causes
them to expand and contract they can
also get overgrown with weeds and grass
so the track ballast is a way to protect
the railroad from all that stuff it
facilitates drainage and prevents the
track from getting flooded it absorbs
vibrations keeps heat expansion at a
safe minimum and doesn't let plants grow
underneath just like the trains and
tracks themselves the ballast also needs
regular maintenance and cleaning if the
rocks get covered in too much mud and
grime
they won't drain water as effectively
okay now that you know all the basics of
railroad ballast because it's what's on
everyone's mind right let's look at some
other fun railroad facts you can bring
up at your next watercolor gathering why
do railroads have gaps now I'm not
talking about the spacing between those
wooden or concrete slabs that have gaps
between them remember what those are
called cross ties bingo or sleepers if
you're in Europe anyway I mean the gaps
between two sections of track isn't
there a risk of the train derailed
of course not while laying the track
engineers leave small gaps so there will
be room for the tracks to expand steel
does exactly that when the temperature
rise it's like on hot summer days the
expansion can also be caused by friction
from the moving train if you don't leave
any gap the rails will expand and buckle
eventually becoming deformed and
dangerous for use how a railway is
protected from rusting rust on railroad
tracks is caused by moisture humidity
freezing temperatures and road salt
those are the factors you can't avoid
entirely when maintaining a rail but
they do have ways of protecting lines
from getting damaged by rust or at least
slow down the process when the railroad
is built they pick high-quality steel
because it's less prone to corrosion
also because of the constant friction
the top and upper sides of a rail are
kept polished and free of rust
but what happens if the inner side
corrodes over time well that's exactly
why they have regular inspections they
keep track of all of the rails and when
it's time to replace part or all of one
that's what they do you can see
especially rusty tracks in a place where
trains no longer pass or just come
through very seldom so the more
abandoned the railroad is the rust year
it may be it turns out that the key to
keeping rust off a track is to use it
regularly is it dangerous to ride on a
train during a thunderstorm well it's
much safer on a train than in an open
field during a storm that's for sure but
it could also be safer than being inside
a building and that comes as a surprise
right after all a train is a big hunk of
metal traveling on even more metal if
you know why airplanes aren't damaged by
lightning then you must be a regular
here on the bright side you'll also know
that aircraft act as a giant Faraday
cage it's the same thing with trains and
it works like this the cage protects the
inside of the Train from electromagnetic
fields also known as lightning by
redirecting the current along the
outside so even if lightning strikes a
train you'll be safe inside even if
you're holding a fork otherwise it could
be a shocking experience
why do trains change tracks while
running well there's the obvious answer
when the track splits and they need to
go that way but here's what surprised me
sometimes two trains operate on the same
track and one needs to get over so the
other can pass this switch allows
traffic to move more efficiently the
switch must be performed smoothly since
the majority of train derailments happen
when a train changes tracks most of the
time the process is so careful and done
so professionally that the passengers
don't even notice what is a railroad
frog a little amphibian that lives on
every line not quite a railroad frog is
the point where the left and right rails
cross at a switch if you look at it from
above you'll see that it looks exactly
like a frog's leg
those frogs will vary in size and styles
depending on the degree of curve they're
numbered according to the size of the
switch with higher numbers corresponding
to larger frogs and more gentle curves
whitey trains blow their horn all the
time
it's obviously not for fun or to
entertain the passengers trains honk for
an array of safety reasons and they
pretty much use a giant air horn to do
it
compressed air gets blown along a metal
plate and this causes a vibration the
vibration makes sound waves and they
travel through and are often made louder
by the horn all the sounds the Train
makes have special meanings but the main
purpose is to instruct or alert people
or animals that a train is coming their
way a long honk means a train is
approaching a station this is made to
attract the attention of everyone on the
platform to long honks mean the brakes
have been released and the train is
starting to move several long whistles
means the train is approaching the
crossing in other words if you're at the
junction don't cross the tracks a
sequence of short toots is heard when
vehicles are livestock or on the tracks
and they need to get out of the way and
just to give you an idea it takes an
average freight train traveling 55 miles
per hour more than the length of 18
football fields to make it to a complete
stop so if you live close to a railroad
maybe next time you're so rudely woken
up by the sound of a train horn you'll
remember that it's all for the sake of
safety hey if you learn something new
today about railroads then give this
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side of life