Why wind socks at switch yards?

[edblysard]

The socks tell us which way to run when something falls over harder that you would like.
Ed

[Anonymous]

...they also help the engineers decide what position to place the sails on the wind powered locomotives.

[BaltACD]

A second purpose of a Wind Sock, since in switching, cars are roling on their own momentum, either from having been 'kicked' by a yard crew or by being cut off rolling over the hump at a hump yard....The wind can make a serious difference in how fast and how far a car will roll.

Wind behind the car can cause it to roll farther and faster than intended. Wind in the face of the car may cause it to stop short of its inteneded destination and may even stop it short enough that it fouls the switching lead, thus creating problems for either the switching or hump crew as they will have to make an additional move to get the car clear of the lead to continue their switching.

[Anonymous]

You are exactly right about the wind socks and their purpose at rail yards. You will also find them at chemical plants, refineries, and other industries that ship or receive hazardous materials.

[Anonymous]

Good afternoon,
I noticed a few years ago that several switching yards in my area put up wind socks. There are 4 of them in a nearby yard here in Wisconsin, which is approx 1 1/2 miles in length.

My best guess is that if you should have a hazardous chemical spill from a derailment, etc that you could quickly determine the direction of downwind drift of the chemical.... but that's just my guess.

Any firm answers on what purpose they serve? Have you seen them elsewhere?
Thx
- Stack