Introducton
This page will introduce some basic concepts necessary for
successful train driving. By successful I mean that you end up
getting the locomotive and its load from A to B in one piece and
without killing anybody in the process.
You might think the above is rather strange as trains only go
where the track leads but this is only half of the story. What we
need to discuss here is when and not where the train goes. Your route
has already been decided and you have no choice but to follow it, so
the question of where becomes irrelevant.
As far as when is concerned what we are interested in is a matter
of physics. Driving on a railway or railroad is nothing like driving
any other vehicle. Put out of your mind that you can drive a car so a
train can’t be that difficult! Your wrong for several basic reasons.
Why is it so hard to stop a
train?
Cars have rubber tyres on tarmac roads trains have steel tyres on
steel roads, I will come back to that point in a moment. A car weighs
about 2 tons a train weighs about 50 to 150 tons + its coaches or
wagons. The problem with trains isn’t starting them it’s stopping
them once you have. My grandfather who was a railwayman for many
years put it quite well when he said "Any idiot can start a train, it
takes skill and practice to stop it where you want it to stop."
"British Rail Class 37" For a high
resolution copy of this drawing click it to download a jpeg file
version (220K)
So how do you stop a train
Steel tyres and steel track don’t make for very good stopping
power. Simply because there is not a great deal of friction between
the two when weights of 300+ tonnes are involved. The inertia
(momentum) of a moving train is very high. Slamming the brakes on
wont stop it, all you will achieve is a skid which lasts for a good
long distance and locked wheels which end up with flat parts on the
tread and a damaged track.
What we need to do, is to progressively retard the rotation so
that the force involved is spread over greater time. (progressive
braking). We achieve this on a railway in several ways. Lets look at
the factors involved. The first one we already mentioned "weight" It
is important that the train weight is reported to the driver before
departure if not or if the wrong train weight is reported he could
end up setting the brake pressure and application rate incorrectly.
This would then result in either the train not stopping when expected
or even accelerating on a gradient with the brakes on. Just as bad,
the damage we have already talked about could occur,costing thousands
of pounds, dollars, spons, wedge, whatever (convert to your own
currency!!!).
The second factor is the track itself, you may think that steel is
steel is steel. This would be far from the truth. In different
weather conditions steel behaves very differently. Steel becomes
greasy when it gets wet, this is because it is partly porous and
retains any oil or grease that has transferred to it and as you all
know oil floats on water. So if it rains it is even harder to stop.
The third factor is the route itself. It has gradients, curves,
speed restrictions etc etc…. A driver must learn the route. This is
usually done from books and a lot of study backed up with real world
knowledge. You have to know where all of the signals are so that you
can stop in time when they are showing red. You have to know how
steep the grades are and where they start and end you have to know
where the curves are, you have to know where the stations and yards
are and last of all you have to know about any special restrictions
or work being carried out on the line on a daily basis.
All of the above is far more important than knowing how to start a
train moving if you want to prevent injury or death!! and get your
load where it is needed.……..