The 49th “Rest Of” Power Plant Post
Originally posted 10/12/2013
Everyone expects when they enter an elevator and push a button for the 3rd floor that when the doors open they will find themselves on the third floor. It doesn’t occur to most people what actually has to happen behind the scenes for the elevator to go through the motions of carrying someone up three stories. In most cases you want an automated system that requires as little interaction as possible.
I have found while working in the Coal-fired Power Plant in North Central Oklahoma that some systems are better off with a little less than perfect automation. We might think about that as we move into a new era of automated cars, robot soldiers and automatic government shutdowns. Let me give you a for instance.
The coal trains that brought the coal from Wyoming all the way down to the plant would enter a building called “The Dumper.” Even though this sounds like a less savory place to park your locomotive, it wasn’t called a Dumper because it was a dump. It was called a Dumper because it “Dumped.” Here is a picture of a dumper:
The coal train would pull into this room one car at a time. I talked about the dumper in an earlier post entitled “Lifecycle of a Power Plant Lump of coal“. As each car is pulled into this building by a large clamp called the “Positioner” (How is that for a name? It is amazing how when finding names for this particular equipment they decided to go with the “practical” words.
The Positioner positions the coal cars precisely in the right position so that after the car clamps come down on the car, it can be rotated upside down “Dumping” the coal into the hoppers below. No fancy names like other parts of the power Plant like the “Tripper Gallery” or the “Generator Bathtub” here.
A typical coal train has 110 cars full of coal when it enters the dumper. In the picture of the dumper above if you look in the upper left corner you will see some windows. This is the Dumper Control Room. This is where someone sits as each car pulls through the dumper and dumps the coal.
Not long after the plant was up and running the entire operation of the dumper was automated. That meant that once put into motion, the dumper and the controls would begin dumping cars and continue operating automatically until the last car was through the dumper.
Let me try to remember the sequence. I know I’ll leave something out because there are a number of steps and it has been a while since I have been so fortunate as to work on the dumper during a malfunction… But here goes…
I remember that the first coal car on the train had to positioned without the positioner because… well….. the car directly in front of the first car is, of course, the locomotive. Usually a Burlington Northern Santa Fe Engine.
Before I explain the process, let me show you a picture of the Positioner. This the machine that pulls the train forward:
The automation begins after the first or second car is dumped. I’ll start with the second car just finishing the process as it rolls back up right after dumping the coal… The car clamps go up.
- The rear holding arm (that holds the car in place from the entrance side of the dumper) lifts up out of the way.
- The Positioner begins pulling the entire train forward.
- Electric eyes on both end of the dumper detect when the next car has entered the dumper.
- The Positioner adjusts the position of the coal car to the exact position (within an inch or two) by backing up and pulling forward a couple of times.
- The Holding arm on the back end comes down on the couplings between the two train cars one back from the car that is going to be dumped.
- The four car clamps come down on the train car at the same time that the dumper begins rotating.
- The Positioner clamp lifts off of the train car couplings.
- Water Sprayers come on that are attached to the top of the dumper so that it wets the coal in order to act as a dust suppression.
- The Positioner travels back to the car clamp between the car that was just emptied before and the car in front of it.
- As the train car rotates to the desired angle. (I think it’s about 145 degrees), it begins slowing down.
- When the car has been rotated as far as desired it comes to a stop.
- The Dumper pauses for a few seconds as all the coal is dumped from the coal car.
- The Positioner moves back and forth until it is in just the right position for the positioner arm to lower onto the couplings between the cars.
- The Sprayers turn off.
- The Dumper begins returning to an upright position.
- The Positioner arm lowers down onto the clamps between the coal cars.
- Once the car is upright the dumper stops rotating.
- The 4 car clamps go up.
- The Holding arm goes up. And the process is repeated.
This is a beautiful process when it works correctly. Before I tell you about the times it doesn’t work correctly, let me tell you about how this process was a little…uh… too automated…
So. The way this worked originally, was that once the automated process was put into operation after the second car had been dumped, all the dumper control room operator had to do was sit there and look out the window at the coal cars being dumped. They may have had some paperwork they were supposed to be doing, like writing down the car numbers as they pulled through the dumper. It seems that paperwork was pretty important back then.
Each car would pull through the dumper… The coal would be dumped. The next car would be pulled in… etc.
Well. Trains come from Wyoming at any time of the day. Train operators were paid pretty well, and the locomotive engineers would come and sit in the control room while the train was being dumped. Often (more often than not it seemed) the trains would pull into the dumper in the middle of the night. Coalyard operators were on duty 24 by 7.
So, imagine this…. Imagine Walt Oswalt… a feisty sandy haired Irishman at the dumper controls around 3 in the morning watching 110 cars pull through the dumper. Dumping coal…. One after the other. I think the time it took to go from dumping one car to the next was about 2 1/2 minutes. So it took about 3 1/2 hours to dump one train (I may be way off on the time… Maybe one of the operators would like to leave a comment below with the exact time).
This meant that the dumper operator had to sit there and watch the coal cars being slowly pulled through the dumper for about 3 hours. Often in the middle of the night.
For anyone who is older than 30 years, you will remember that the last car on a train was called a Caboose. The locomotive engineers called it a “Weight Car”. This made me think that it was heavy. I don’t know. It didn’t look all that heavy to me… You decide for yourself:
Back in those days, there was a caboose on the back of every train. A person used to sit in there while the train was going down the tracks. I think it was in case the back part of the train accidentally became disconnected from the front of the train, someone would be back there to notice. That’s my guess. Anyway. Later on, a sensor was placed on the last car instead of a caboose. That’s why you don’t see them today. Or maybe it was because of something that happened one night…
You see… it isn’t easy for Walt Oswalt (I don’t mean to imply that it was Walt that was there that night.. well… it sounds like I’m implying that doesn’t it…. I use Walt when telling this story because he wouldn’t mind. I really don’t remember who it was) to keep his eyes open and attentive for 3 straight hours. Anyway… One night while the coal cars were going through the dumper automatically being dumped one by one… there was a point when the sprayers stopped spraying and the 4 car clamps rose, and there there was a moment of pause, if someone had been there to listen very carefully, they might have heard a faint snoring sound coming from the dumper control room.
That is all fine and dandy until the final car rolled into the dumper. You see… One night…. while all the creatures were sleeping (even a mouse)… the car clamps came down on the caboose. Normally the car clamps had to be raised to a higher position to keep them from tearing the top section off of the caboose.
If it had been Walt… He woke when he heard the crunching sound of the top of the caboose just in time to see the caboose as it swung upside down. He was a little too late hitting the emergency stop button. The caboose rolled over. Paused for a moment as the person manning the caboose came to a rest on the ceiling inside… then rolled back upright all dripping wet from the sprayer that had meant to keep down the dust.
As the car clamps came up… a man darted out the back of the caboose. He ran out of the dumper…. knelt down… kissed the ground… and decided from that moment on that he was going to start going back to church every Sunday. Ok. I exaggerate a little. He really limped out of the dumper.
Needless to say. A decision had to be made. It was decided that there can be too much automation at times. The relay logic was adjusted so that at the critical point where the dumper decides to dump a coal car, it had to pause and wait until the control room operator toggled the “Dump” switch on the control panel. This meant that the operator had to actively decide to dump each car.
As a software programmer…. I would have come up with another solution… such as a caboose detector…. But given the power that was being exerted when each car was being dumped it was probably a good idea that you guaranteed that the dumper control room operator actually had his eyeballs pointed toward the car being dumped instead of rolled back in his head.
I leave you with that thought as I go to another story. I will wait until another time to talk about all the times I was called out at night when the dumper had failed to function.
This is a short story of durability…
I walked in the electric shop one day as an electrician trainee in 1984 to find that Andy Tubbs had taken an old drill and hooked it up to the 480 volt power source that we used to test motors. Ok. This was an odd site. We had a three phase switch on the wall with a fairly large cable attached with three large clips so we could hook them up to motors that we had overhauled to test the amperage that they pulled to make sure they were within the specified amount according to their nameplate.
I hesitated a moment, but I couldn’t resist…. I had to ask, “Andy…. Why have you hooked up that old drill to 480? (it was a 120 volt drill). He replied matter-of-factly (Factly? Can I really say that in public?), “I am going to burn up this old drill from the Osage Plant (See “Pioneers of Power Plant Fame Finally Find Peace” for more information about Osage Plant) so that I can turn it in for a new one.
Ok. I figured there must be a policy somewhere that said that if you turned in a burned up tool they would give you a new one. I knew that Bud Schoonover down at the toolroom was always particular about how he passed out new tools (I have experienced the same thing at my new job when trying to obtain a new security cable for my laptop).
Anyway. Andy turned the 480 volts on and powered up the drill. The drill began whining as it whirled wildly. Andy stood there holding up the drill as it ran in turbo mode for about five minutes. The drill performed like a champ.
After showing no signs of burning itself up running on 480 volts instead of 120 volts, Andy let off of the trigger and set it back on the workbench. He said, “This is one tough drill! I think I’ll keep it.” Sure. It looked like something from the 1950’s (and it probably was). But, as Andy said, it was one tough drill. On that day, because of the extra Durability of that old Pioneer Power Plant Drill, Andy was robbed of a new variable speed, reversible drill that he was so craving.
Comments from original post:
It takes about 7 hrs to dump 150 car train
Wasn’t Walt but a certain marine we won’t mention. They dumped the last car & forgot to put the car clamps in the up maximum position. They give the go ahead for the train to pull the caboose through! Instant convertible caboose! Now there are break away clamps on the north side. And there are locomotives on the rear of the train because the trains are made up of 150 cars .
Like you, I can think of several ways to automate the process without dumping the caboose but I think the operator pushing the button may be the best. Automation can get out of hand.