Most modern diesel locomotives are actually diesel-powered electrical generators on rail wheels. The electricity from the diesel engine is fed to electric motors on the wheels. The engine is not directly connected to the wheels through a driveshaft like most diesel-powered road vehicles. Most diesel locomotives with which I'm familiar have eight "notches" of power, known as "Run 1" through "Run 8."
The engineer explained that no matter where he set the power selector, the lead locomotive (and at least one of the remote-controlled locomotives farther back in the train) was displaying Run 8. Fortunately, he was able to disengage the electric motors from the engine. He then was able to use the air brakes to bring the train to a halt here in Fernley. This is sort of like if you were driving a manual transmission car and the throttle got stuck wide open, but you were able to hold the clutch down and shift into neutral while applying the brakes. It works, but it's unnerving, and also loud.
I had just barely enough time to get my camera-phone engaged and shot a very brief bit of footage of the train coming by with the lead locomotive's engine running a full tilt but not transmitting any power to the wheels, while the train slowed to a halt. The train stopped with its tail fouling the switch behind it at West Fernley, and it was dangerous to move in this situation, so the entire Nevada Subdivision ground to a halt as there was no way to get trains around this one.
Once the train was stopped, the crew discussed options. (I only could hear this because they'd stopped in Fernley, where it is relatively flat and straight, and that was a good thing when trying to stop a potential runaway. Because of this, I could hear the train crew as well as the dispatcher.) The dispatcher put them in touch with the UP Help Desk. The Help Desk essentially told them to reboot the locomotive, or at least the parts of it running the train-optimization software that is supposed to run the train at the optimal speed and save fuel. In addition, the crew got in contact with the PTC Help Desk. PTC is "Positive Train Control," the system that stops trains if they overrun signals or go too fast. The engineer reported that the PTC on this locomotive was not behaving properly, and he was worried that even if they got the initial software issue resolved that the PTC would override things again. There was no guarantee that the next "runaway" would be on a nice easy stretch of railroad like Fernley.
After more than an hour of back-and-forthing (including Sparks Yard sending someone out to have a look at the locomotive), they got it sufficiently reset to work again, the PTC desk said it was okay to disable the PTC if the dispatcher agreed, and the dispatcher said it was okay if the PTC desk said so. With PTC disabled and the fuel-optimization program also disabled, the engineer felt safe enough to re-engage the engine and slowly pull away, heading east. The dispatcher was relieved, not just because there was no catastrophe, but because there were multiple trains converging on Fernley and the worried dispatcher had nowhere to put them. Everyone breathed a sign of relief, but not a very deep one because of the growing smoke.
I took these pictures while the disabled train was parked on Fernley's main line. The wind has shifted back to a more normal pattern, and that means the smoke from the California fires is back with a vengeance.
The camera makes it look less smoky than it was.
Even without the stopped train, you would not have been able to see I-80 from here, and it's normally clearly visible.
Fernley is surrounded by hills and mountains on all sides, but you wouldn't have known it today.
Now this isn't anywhere near as bad as the smoke in the Bay Area and the Willamette Valley, where I understand the AQI was over 500 (unsafe for everyone). But it was certainly noticeable. My eyes started watering again and my throat burned with the smoke. I'm very glad that I can stay inside and run the swamp cooler, which does pull some of the smoke out of the air. Those people who have to be out in this, particularly the fire fighters trying to put out these fires, have my gratitude.
I only hope that the wind shift means that the fires are being pushed back over already burned-out areas, which might make it easier to put it out.
My father's home is in the evacuation area, and the fire maps this morning that purport to show areas actually burning (not the "heat maps" that cover a larger area) do not yet cover his house, but they're awfully close, as the fire is now on the south side of Lake Oroville. My only contact for my father is his home landline phone, and I don't even know if he has a mobile phone, so I have not been in contact with him.