"Jim Carr" wrote in message
news:1gVUc.10087$yh.1675@fed1read05
"Arny Krueger" wrote in message
...

That's because the train is not moving back and forth in front of
us, in a periodic sine-shaped pattern.

You OBVIOUSLY have not seen the trains in America!

LOL!

There's a crossing I frequent north of here that must have a lot of trains
doing switching, that seem to specialize in repetitive, back-and-forth
movements.