Lightning arresters are an often overlooked item when thinking of railroad signals, but since almost any and everything in a signal plant is made out of metal, INCLUDING the track, it can ALL attract lightning.
Lightning arresters work by transferring the electrical spike created from the lightning strike, to ground, where it can be bled off and hopefully do no further harm. In the process, most lightning arresters sacrifice themselves, and need to be replaced since they are now electrically shorted.
Photos supplied by Abram B. unless noted.
A collection of four of the devices.
An arrester made by LM - the Line Material Company in NY. It's rated for a 6KV flashover.
The above lightning arresters work in a similar fashion to those made today.
A quick overview of how they work is provided below, material provided by http://www.arresterworks.com/
and comes from the following PDF: http://www.arresterworks.com/pdf_file/what_is_an_arrester.pdf
This principle is also used in the surge protectors you use (or should use) around the home to protect sensitive electronics, like TV, audio equipment, computers, etc, etc. Inside the surge protectors, they use things called MOV's, and are depicted below.
The above pictures are used with permission by Mr. Jonathan Woodworth... Many Thanks!
Last Modified 16-Nov-2013