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Re: Occupy a Hi-Wide detector...why there?
Author: OPRRMS
Date: 11-03-2011 - 22:58
Severe Duty Wrote:
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> What was the need for it there? Ususally, Hi-Wides
> are a couple of miles ahead of what they protect.
> What was in the area for that needed protection?
After the larger domestic containers were introduced, SP began experiencing a number of incidents where domestic containers stacked two high struck impaired clearances such as tunnels, so SP constructed two Excess Height detectors that outbound trains handling double stacks would need to pass under when leaving Oakland, along with instructions that prohibited stacking two domestic containers on top of one another. The one pictured in the lead post on this thread was used by trains departing via Magnolia. The other one was installed about a hundred yards east of the BART overpass and used by trains leaving towards Martinez. The idea was to detect any load that exceeded the allowable height while the train was departing the yard, so the car could be set out. Trains that were built at either the Desert or Homestead from multiple cuts loaded at the intermodal ramp would've already passed under the respective detector as they were dragged out.
Each detector spanned two tracks. An electric eye system was mounted on the vertical aluminum pipes that you can see in the photo, and any load that was higher than the allowable limit would "break" the eye's beam.
Both detectors also had paddle boards mounted on the ties to detect any dragging equipment.
The detectors were no longer needed once the clearances had been adjusted, so their use was discontinued and the eyes removed, although the structures remain in place (although after Wednessday's activities, we'll see for how long).
-------------------------------------------------------
> What was the need for it there? Ususally, Hi-Wides
> are a couple of miles ahead of what they protect.
> What was in the area for that needed protection?
After the larger domestic containers were introduced, SP began experiencing a number of incidents where domestic containers stacked two high struck impaired clearances such as tunnels, so SP constructed two Excess Height detectors that outbound trains handling double stacks would need to pass under when leaving Oakland, along with instructions that prohibited stacking two domestic containers on top of one another. The one pictured in the lead post on this thread was used by trains departing via Magnolia. The other one was installed about a hundred yards east of the BART overpass and used by trains leaving towards Martinez. The idea was to detect any load that exceeded the allowable height while the train was departing the yard, so the car could be set out. Trains that were built at either the Desert or Homestead from multiple cuts loaded at the intermodal ramp would've already passed under the respective detector as they were dragged out.
Each detector spanned two tracks. An electric eye system was mounted on the vertical aluminum pipes that you can see in the photo, and any load that was higher than the allowable limit would "break" the eye's beam.
Both detectors also had paddle boards mounted on the ties to detect any dragging equipment.
The detectors were no longer needed once the clearances had been adjusted, so their use was discontinued and the eyes removed, although the structures remain in place (although after Wednessday's activities, we'll see for how long).
