Jim G Wrote:
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> 2nd question: I hear Dispatcher 41 (Spokane
> Subdivison dispatcher)give instructions to the
> train crews and he sometimes refer to Papa Sierra
> representing PS. What does this stand for ?

PS is likely "Procedure PS"

From the UP System Special Instructions:

Procedure PS
When required by the train dispatcher (either verbally or by track warrant) to comply with procedure PS, approach switches prepared to stop and line switches to their normal position. Crew member or employee must advise the train dispatcher when it is known switches are lined in their normal position.