This isn't related to a car rolling on its own, but I was on a B&B gang that
had to move a material gon a few fit on a spur track, and 5 of us were able to
move it (by pushing and using pinch bars) on level track with the brakes
released. It was then that I realized it doesn't take much effort to get a
freight car to roll.
Glen Haug
To: CBQ@yahoogroups.com
From: js08ws62@sbcglobal.net
Date: Sun, 15 Nov 2009 03:47:26 +0000
Subject: [CBQ] Railroad Freight Cars Moving on Their Own
It seems to me that everyone on this list is here because we admire, love, and
are generally curious about all the aspects of railroading. So, this question,
though off-topic, might be of general interest to all, and of specific interest
to those who know physics.
Railroading began and continues to be a popular and effective way of moving
freight because a rolling steel wheel on a steel rail is very efficient. I have
seen reports that an 8- wheel freight car rests on less than 2 square inches.
And, it is steel on steel - little friction. Moreover, I am sure all of us have
witnessed the very long distances that a very slow moving freight car can roll
on its own. It is phenomenal. So? here's a theoretical question:
If an ordinary, empty, boxcar resting on 2 roller-bearing 4-wheel trucks was
given a 50 mile an hour push on a perfectly level, perfectly straight railroad
track on a windless day, how far would it go before stopping on its own?
It also would be interesting to hear some of your stories known from personal
experience regarding long distances rolled by railroad cars moving on their
own. Another phenomenon worthy of comment would be just how silently they roll.
I'm sure many have stories about that, too.
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