TKM wrote:

"Sawney Beane" wrote in message
...


There are different parts of a rail to measure from, so I took a
steel tape to measure the track alongside the municipal parking
lot. While I was there, the crossing arms came down and traffic
backed up and no train came.

I went home, thought it over, and returned to check my
measurements. A railroad truck turned in, raced across the parking
lot, and screeched to a stop. A mean-looking railroad man jumped
out and demanded to know what I thought I was doing. I nervously
began my explanation, "Well, Click and Clack said..." Uh-oh, I'd
really put my foot in my mouth! I realized most people had never
heard of Click and Clack.

The following week, the Tappet Brothers announced the answer: early
railroaders had decided that their cars should have the same
wheelbase as Roman chariots. What a myth! I almost went to the
funny farm for a brain teaser that was beneath contempt.

Well, you've probably figured out that your steel tape completed a circuit
between the two rails within a "block" (an electrically isolated stretch of
rails that controls a set of signals). The circuit is powered by batteries,
but I've forgotten the battery voltage. However, it's not enough to cause
electrocution should you straddle the rails with bare feet. If you look at
the rail joints, you will see a braided wire fastened to each side so the
circuit is continuous and reliable. The system has been used for many years
and is standard in the U.S. Today, there's probably a line to a computer
somewhere that indicates which blocks are active (indicating the presence of
a train or a fault. Maybe that's what brought the railroad truck and its
hostile occupant to check you out.

Terry McGowan

I was a little self-conscious measuring the rails because I figured
it was trespassing, technically. So when the truck raced up I was
embarrassed and startled that I'd drawn such a response. The
driver hadn't shaved and reminded me of the guard who clubbed Cool
Hand Luke into the grave-sized hole.

When he asked if my tape was steel, I caught on. I had read
somewhere about the signal voltage in rails. That made it worse
because now I couldn't honestly claim ignorance. If anything could
have made the situation more embarrassing, it was to realize I had
started explaining about my invisible friends, Click and Clack, who
had told me to do it.

The crossing a few yards from where I measured is notorious because
the gates often come down when there is no train. If they stay
down, the railroad may take 45 minutes to respond. I wonder why
they can't master the technology.

There's also a squashed head near where I measured. I think that's
what it's called. It starts when an engineer spins his wheels,
which overheats and gouges the rail. Then the damaged area becomes
a sort of pothole. When steel wheels hit it, the racket is
unpleasant half a mile away. It shortens the life of the wheels,
but the railroad doesn't bother to replace the rail.