Every Red Line platform of late has an "arrow" (really just two 3"-wide pieces of tape mounted at a right angle) pointed a a survey spike with a reference number written alongside. What are these for?
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Yellow tape arrow on platforms
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I've noticed them on the Orange and I think even some Green Line platforms in the last few weeks as well.
Wondering if I'll see the Western Route double-tracking finished before I retire...
Photo: Melbourne W7 No. 1019 on Route 78, Bridge & Church Streets, Richmond, Victoria. 10/21/2010
Photo: Melbourne W7 No. 1019 on Route 78, Bridge & Church Streets, Richmond, Victoria. 10/21/2010
octr202 wrote:I've noticed them on the Orange and I think even some Green Line platforms in the last few weeks as well.I noticed them at the rear ends of Downtown Crossing and Tufts Medical Center yesterday. Could be a stopping point when running wrong-rail.
Gerry. STM/BSRA
The next stop is Washington. Change for Forest Hills Trains on the Winter St. Platform, and Everett Trains on the Summer St. Platform. This is an Ashmont train, change for Braintree at Columbia.
The next stop is Washington. Change for Forest Hills Trains on the Winter St. Platform, and Everett Trains on the Summer St. Platform. This is an Ashmont train, change for Braintree at Columbia.
So far they appear to be at both ends of the platform.
Wondering if I'll see the Western Route double-tracking finished before I retire...
Photo: Melbourne W7 No. 1019 on Route 78, Bridge & Church Streets, Richmond, Victoria. 10/21/2010
Photo: Melbourne W7 No. 1019 on Route 78, Bridge & Church Streets, Richmond, Victoria. 10/21/2010
I have seen them on both the Orange & Green Lines. I noticed on some of them a small surveying marker at the arrow point, also a number written in yellow.
My guess measuring the property for the real estate agent
!
JoeD
My guess measuring the property for the real estate agent
!JoeD
JoeD
This message was sent from a DEC VT100!
This message was sent from a DEC VT100!
Gerry6309 wrote:Could be a stopping point when running wrong-rail.Saw one at the north end of the southbound platform at State today. It lined up with the cab window at the rear of the train. I'm almost inclined to suspect they're installing a screen for running wrong-iron or for short turning. It would certainly be necessary in some cases with some of the ever-so-gently curved platforms downtown.
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I saw one at Central on the red line today, Alewife-bound side.
At the station formerly known as Mechanics!
JoeD
JoeD
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JoeD
This message was sent from a DEC VT100!
This message was sent from a DEC VT100!
They're systemwide, and not only on platforms.
Moderator: Massachusetts Bay Transportation Authority, Brightline Trains
Avatar:3679A (since wrecked)/3623B (now in service as 3636B).
Avatar:3679A (since wrecked)/3623B (now in service as 3636B).
I saw one at Packard's Corner today as well.
If they are also showing up on Blue Line platforms, that blows my theory that it has to do with measurements for the new cars (Red / Orange and Type 9 Green).
My next-best theory is it has to do with the video surveillance that's been installed at the ends of almost every platform. I have yet to get this confirmed, but as far as I can tell there are cameras at every tunnel entrance and platform end backed by motion-sensing video processing. I believe that's why there is a ID reader PIN-pad with the red LED at every platform end. I'm speculating that if someone enters the tunnel and/or goes beyond the end of the platform the video surveillance would pick them up and alert Transit Police, unless they had signed-in first on that PIN keypad.
If I"m right about that, then the yellow arrow tape markers could be used to calibrate / test the video surveillance.
My next-best theory is it has to do with the video surveillance that's been installed at the ends of almost every platform. I have yet to get this confirmed, but as far as I can tell there are cameras at every tunnel entrance and platform end backed by motion-sensing video processing. I believe that's why there is a ID reader PIN-pad with the red LED at every platform end. I'm speculating that if someone enters the tunnel and/or goes beyond the end of the platform the video surveillance would pick them up and alert Transit Police, unless they had signed-in first on that PIN keypad.
If I"m right about that, then the yellow arrow tape markers could be used to calibrate / test the video surveillance.
The Blue Line is good for Lynn, and Lynn is good for the Blue Line.
My live MBTA real-time mapping apps:
https://sites.harvard.edu/~wuensch/T/subway-map.html
https://sites.harvard.edu/~wuensch/T/commuter-rail-map.html
My live MBTA real-time mapping apps:
https://sites.harvard.edu/~wuensch/T/subway-map.html
https://sites.harvard.edu/~wuensch/T/commuter-rail-map.html
StefanW wrote:...the yellow arrow tape markers could be used to calibrate / test the video surveillance.However if the arrows are also on above-ground stations that blows that theory also... unless there are general-purpose security cameras also above ground...?
Is there any video surveillance at Packard's Corner?
The Blue Line is good for Lynn, and Lynn is good for the Blue Line.
My live MBTA real-time mapping apps:
https://sites.harvard.edu/~wuensch/T/subway-map.html
https://sites.harvard.edu/~wuensch/T/commuter-rail-map.html
My live MBTA real-time mapping apps:
https://sites.harvard.edu/~wuensch/T/subway-map.html
https://sites.harvard.edu/~wuensch/T/commuter-rail-map.html
A friend who is an Inspector on Rapid Transit confirms the marks are for a GPS survey that was recently done. Once in the tunnel, he says, they had
a limited time for accurate surveying due to loss of GPS signal.
a limited time for accurate surveying due to loss of GPS signal.
Diverging Route wrote:A friend who is an Inspector on Rapid Transit confirms the marks are for a GPS survey that was recently done. Once in the tunnel, he says, they hadThe markers are reference points for old-fashioned surveying. GPS becomes unusable for surveying the instant you lose direct line-of-sight to GPS satellites.
a limited time for accurate surveying due to loss of GPS signal.
