Have a SAFE and HAPPY SWSAT, everyone!
On the PER a little drama:
While the Main has crossing lights the East End lead does not so the Conductor has the additional work of flagging that crossing. This complicates switching the East End. As well, a train cannot block either crossing for extended periods of time so the length of the train in foreground is limited without fouling the East End switch (off to the right) which can further complicate the day's Job.
Set to pull the West End siding:
While switching the West End the Engineer gets to watch this pump-jack at work lifting Pennsylvania Crude to the surface:
Western Pa illustrates the principle of Peak Oil. After all these years (starting in 1859 at Drake's Well) of extracting oil half of it is still in the ground there. BUT, when each new barrel is extracted the flow rate on that well decreases (by a tiny amount) so over time the flow rate approaches but never reaches zero. The speed of the pump jacks is geared down and down over time. By now wells in Western Pa are left to rest most of the time (giving crude time to slowly seep into the rock zone available to the well) with pump jacks operating for a few hours at a time. And so it goes around the World. Probably the most closely held secret in the oil biz is the flow rate of wells, especially newer plays with unconventional [Frack] wells. Indications are that Frack wells play out much sooner than conventional wells and this knowledge could/can tank investment in new plays.