Trip Arms and IDENTRA and...

[kitn1mcc]

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

[Kamen Rider]

never seen the trip arm before?

[kitn1mcc]

knew i should have taken a pic

[Fan Railer]

knew i should have taken a pic

http://www.nycsubway.org/articles/signals_stops.html
this might enlighten you...

[railfaned]

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???

[jtunnel]

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

[Kamen Rider]

the system, called "IDENTRA" was a magnet, which would align the route for express or local.

[jtunnel]

Cool, thanks!

http://www.thejoekorner.com/out-the-front/signals.htm

[kitn1mcc]

thanks guys

[railfaned]

My Thanks also!!!

[Patrick Boylan]

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]

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

[Patrick Boylan]

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

[kitn1mcc]

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