Trip Arms and IDENTRA and...

Discussion relating to the past and present operations of the NYC Subway, PATH, and Staten Island Railway (SIRT).

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kitn1mcc
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Trip Arms and IDENTRA and...

Post by kitn1mcc » Tue Dec 01, 2009 7:25 pm

i was in BK this weekend got on the L at the bedford station. i was looking around as normal. i noticed next to the tracks was a yellow handle sticking up. there was a signal there as well. when the train got closer the handle went down. but the signal stayed red. whats that handle thingy do
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Kamen Rider
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Re: yellow handle along side of tracks on the L

Post by Kamen Rider » Tue Dec 01, 2009 8:08 pm

never seen the trip arm before?
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kitn1mcc
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Re: yellow handle along side of tracks on the L

Post by kitn1mcc » Tue Dec 01, 2009 9:50 pm

knew i should have taken a pic
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Fan Railer
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Re: yellow handle along side of tracks on the L

Post by Fan Railer » Tue Dec 01, 2009 10:02 pm

kitn1mcc wrote:knew i should have taken a pic
http://www.nycsubway.org/articles/signals_stops.html
this might enlighten you...

railfaned
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Re: yellow handle along side of tracks on the L

Post by railfaned » Wed Dec 02, 2009 4:15 pm

While I've always understood the trip arm operation, I could never understand how on the 7 line, the use of the signal hoop that the motorman would put on the head-end of the train in the 60's - 70's. I remember them being used on the R-12's, R15's and R-36's. Can anyone explain how the hoop worked. I remember seeing yellow trips hanging on the signals, but it always seemed that it wouldn't contact the hoops, without hitting the front of the train???
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jtunnel
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Re: yellow handle along side of tracks on the L

Post by jtunnel » Wed Dec 02, 2009 7:54 pm

I thought that hoop was an antenna for the train radio system. Later replaced with the familiar "sinclair" antennas on the equipment.

Kamen Rider
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Re: yellow handle along side of tracks on the L

Post by Kamen Rider » Wed Dec 02, 2009 8:25 pm

the system, called "IDENTRA" was a magnet, which would align the route for express or local.
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jtunnel
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Re: yellow handle along side of tracks on the L

Post by jtunnel » Wed Dec 02, 2009 8:35 pm


kitn1mcc
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Location: Old Lyme CT

Re: yellow handle along side of tracks on the L

Post by kitn1mcc » Wed Dec 02, 2009 9:13 pm

thanks guys
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railfaned
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Re: yellow handle along side of tracks on the L

Post by railfaned » Thu Dec 03, 2009 9:08 am

My Thanks also!!!
ED,
40 year commuter-railfan and model railroader,
Ex-Long Islander

Patrick Boylan
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Re: yellow handle along side of tracks on the L

Post by Patrick Boylan » Thu Dec 10, 2009 9:21 am

Kamen Rider, my dad had told me the Identra hoop was a passive sonar reflector. His explanation didn't make much sense to me since I thought there'd be too much noise in the subway for sonar to be effective.
I also am not sure your magnet explanation works. Wouldn't whatever magnetic device reads the hoop have to be extremely close, or extremely powerful?
A bit of google searching seems to say that it's a radio or radar reflector, which kind of makes more sense.

kitn1mcc
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Re: yellow handle along side of tracks on the L

Post by kitn1mcc » Thu Dec 10, 2009 10:14 pm

i would say radar is not likely. but and magnetic pickup sounds like it would be easy thing to do. or also Low Frequency could work too
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Patrick Boylan
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Re: yellow handle along side of tracks on the L

Post by Patrick Boylan » Fri Dec 11, 2009 10:47 am

Scientifically ignorant as I am I would think radar and low frequency are both forms of radio detection

kitn1mcc
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Re: yellow handle along side of tracks on the L

Post by kitn1mcc » Sun Dec 13, 2009 1:43 pm

Radar is at the 10GHZ+range LF is is about 20HZ
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