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Ken Griffin - Fwd: West Sandy Lake
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Glenn Hollowell
Ken Griffin
12/20/2006 2:33 PM
Fwd: West Sandy Lake
>>> Per Birdsall 12/19/06 4:00 PM >>>
I now have been approached by our signal contractor out on Sandy Lake several times. Some of the items being
asked are simply field changes that are easily handled but several items cannot.
I have been informed that the signal cabinets are not equipped with a confirmation light panel. I was not aware
of their need but certainly it was obvious we desired to have confirmation lights installed. I don't know if this
should be our oversight in not specifying it in the specifications or an oversight of the contractor since it was
clear that our intentions were to have confirmation lights. The panel separates the confirmation lights from the
safety monitor. If the lights are spliced directly into the phase wiring, there is the potential for a phase to be
dark when red without detection by the safety monitor.
I have been told that our specifications call for only one opticom card per intersection. The cards typically come
in a 2 channel configuration. One channel is required for each direction for which preemption is needed. 2 cards
would be required for the intersections on Sandy Lake unless both east and west are on a single channel. This
configuration would not provide protection of the left turn movements at each intersection.
The last change being recommended is for a 7 conductor cable to be replaced by a 16 conductor cable. The
future foundation of the southbound mast arm that will be utilized by a pedestrian pole at Freeport, has a 7
conductor identified for use and is sufficient for it's current usage. A 16 conductor would be of a minor increase
in cost compared to the removal of the 7 conductor and installation of a 16 conductor when the future addition
occurs. I can support this change only if the future is nearer rather than farther.
On a separate note, the Macarthur signals don't have confirmation panels either.
We should evaluate the need to post "No Right Turn on Red" for the westbound direction at Bethel School due
to some visibility obstruction and the curve.
Per
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