signal answer

NW Mailing List nw-mailing-list at
Thu Jun 29 21:31:41 EDT 2017

According to the caption for this photo this is a lite set of pusher power moving westbound into the eastend of Elkhorn tunnel  These units (probably two) have just passed under the westbound signal and are moving away from the signal.  When a train passes under a signal governing its movement it take a few seconds after passing over the bond to break the circuit and to register or change the indication of signal.  When I was working and riding a trailing locomotive I would observe that running track speed, once the lead locomotive passed the signal the signal indication would not drop usually until the second or third locomotive was passing the signal.  I'm sure if the photographer had snapped a second photo the signal would be displaying all red.
Next time you are out railfanning try to notice how long it take for a signal to change indication once a train has passed under it.

-Jeff Hensley.

Who's up for another round of "Signals for Dummies"?

Can somebody explain this:

RailPictures.Net Photo: NS 8086 Norfolk Southern GE ES44AC ...<>
High quality photograph of Norfolk Southern GE ES44AC # NS 8086 at Near Coopers, West Virginia, USA.

How can the signal be green when a train is coming?

Carl Woods
Richmond, VA

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