Pellet unloading sucks

Literally - they used pneumatic unloading, a.k.a. sucking the pellets out the special pellet gates (I assume you also noticed that pellet cars have different gates than grain or sand hoppers).

Each gate has a hose fitting with a cover on each side.  To unload from one of the gates, they hook up a hose to one side of the gate, and put a air intack filter sort of fitting on the other side.  The air moving across the tube in the gate pulls the pellets along the hose - if you’re standing near the hose or the long pipes the hose often connects to that leads to a silo you’ll hear a whooshing sound as the pellets scoot along inside.

Here’s a photo of a car with one of the caps off and a little pile of pellets that escaped:

http://photos.nerail.org/s/?p=176547

Another car at the same small industry - you can make out the pipes on the building side of the track, and the end of one of the hoses draped over a pipe.

Sometimes the pellet cars are transloaded straight into a truck:

Big Hoover

Pellet hoppers are almost always 4-bay covered hoppers with tight-sealing round hatches (typically 20 to 24 inches in diameter, so smaller than cement hopper hatches) and pneumatic outlets.  Pneumatic outlets are unloaded with a vacuum system that moves the product around the plant.  There is no provision for dumping the pellets into a pit, unless you want to pick the car up, turn it over, and shake the pellets out....

One hatch variation that was pretty much standard by 2000 is the "butterfly" hatch.  These are hatches that relieve negative pressure (aka a vacuum) in the compartments.  Each compartment has one butterfly hatch and one or two regular round hatches.  On cars without butterflies a worker has to crack open one hatch per compartment, which means he or she has to climb atop the car.  At best a hassle.  If you don't vent the compartments atmospheric pressure will crush the car as the vacuum unloads it.

It is very helpful to mention which scale you are modeling in when asking for product help.

Scott Chatfield

Scale Plastic Pellet Cars

Scott,

Duh, yeah I forgot.  I model HO.

The Pits

No dumping pits for plastic pellets.

As noted in Ken's [and Scott's, posted while writing this] reply, plastic pellets are shipped in cars with special pneumatic outlets, not standard bottom-dump gravity outlets.

That's one thing that really stands out to me in a lot of model railroad photos/videos: a "grain train" passing with all sorts of pneumatic discharge hoppers, or a bunch of gravity discharge hoppers spotted at the plastic industry. (Especially when they've gone and kitbashed and super-detailed accurate locomotives to the era and region on the head end. And especially when it's published in a magazine like MR or MRH.)

While I understand many modelers simply don't understand or haven't noticed the difference, once you do, it's very distinctive. The "best" of course is that old Athearn abomination of an ACF centre-flow hopper with pneumatic style discharge bays and large trough-style hatches, which wouldn't really co-exist in real life.

Standard outlet (simple gravity dump):

http://canadianfreightcargallery.ca/cgi-bin/image.pl?o=admx&i=admx52454detail3

http://canadianfreightcargallery.ca/cgi-bin/image.pl?o=axlx&i=axlx20057detail2

http://canadianfreightcargallery.ca/cgi-bin/image.pl?o=wfrx&i=wfrx865014detail4

Pneumatic outlet (product sucked out via vacuum hose):

http://canadianfreightcargallery.ca/cgi-bin/image.pl?i=rdix20137detail3&o=rdix

Combination gravity-pneumatic outlets, allowing both types of unloading:

http://canadianfreightcargallery.ca/cgi-bin/image.pl?i=wfrx446602detail1&o=wfrx

http://canadianfreightcargallery.ca/cgi-bin/image.pl?o=sp&i=sp496664detail3

Pressure-differential outlet piping: (fine or powdered product blown out by pressurizing car)

http://canadianfreightcargallery.ca/cgi-bin/image.pl?o=procor&i=unpx26127detail2

http://canadianfreightcargallery.ca/cgi-bin/image.pl?i=cglx60703detail1&o=cgtx

http://canadianfreightcargallery.ca/cgi-bin/image.pl?i=cglx60717detail1&o=cgtx

http://canadianfreightcargallery.ca/cgi-bin/image.pl?i=cslx01detail1&o=cslx

"Butterfly" valve outlets generally unique to carbon black (essentially soot - pretty much the finest grain product out there) service cars:

http://canadianfreightcargallery.ca/cgi-bin/image.pl?i=srcx1933detail2&o=srcx

Sparger outlets for sodium chlorate service cars. Hot water is injected to dissolve and unload the product as a slurry or solution.

http://canadianfreightcargallery.ca/cgi-bin/image.pl?i=unpx120415detail1&o=procor

http://canadianfreightcargallery.ca/cgi-bin/image.pl?i=cglx238&o=cgtx

http://canadianfreightcargallery.ca/cgi-bin/image.pl?i=shpx432773&o=shpx

Unloading

Searching for images of "vaccum railcar unloading": 

Portable system

Fixed systems:

HO pellet hoppers

The most common pellet hopper in the real world is the ACF Center Flow with volumes between 5701cf and 6400cf.  Atlas makes a model of the CF5701 that was built in large quantities in the '80s and early '90s.  This should be your go-to pellet hopper.  Note that Atlas also made the version of the CF5701 with gravity gates (outlets) for dried grain service.  The yellow and blue ADM cars are examples and you don't want them for pellet service.

The next most common pellet hopper by the 2000s was National Steel Car's design, which at that time came in three sizes.  Walthers makes the largest which holds 6245cf.  If memory serves, production of the real NSC-6245s started in 1996.  Again, Walthers also made the dried grain version, so check out the outlets before buying.

There are some rib-side pellet hoppers that were made by Pullman then Trinity, but they are even less common than the Nationals.  Overland made the Pullman a long time ago.  Figure to spend $150 if you can even find one.

Overland also made the rarest of the pellet hoppers, Richmond Tank Car's 5750cf design.  It looks like a Center Flow in a mini skirt.  You'll need a couple hundred Center Flows to justify having one Richmond if ratios bother you.

Lastly, there's the old and tired Athearn 4-bay Center Flow, which represents an early (1960s built) version of the smaller 5250cf Center Flow.  These were mostly built for plastic resins so they were quite unlikely to been seen in pellet service in 2000.  Atlas has announced they will make this car soon. 

And yes, the Bachmann and Tyco 4-bays are copies of the old Athearn, faithfully copying its errors too.  The Tyco even added the error of having a trough hatch on one end and round hatches on the other, a variation that only existed in the advertisement they copied.

And making the old Athearn look good by comparison was the Front Range 4-bay, which was supposed to be a CF5701 but was a dog of a kit.  A Straight-to-landfill model.

And remember, to paraphrase Henry Ford, you can paint your pellet hoppers any color you like as long as it's light grey.

Scott Chatfield

And...

You can use a LOT of pellet hoppers if you model the right places.....

Pellets pellets and more dang pellets.....

Mr. Husman's photo shows a storage-in-transit (SIT) yard, where pellet hoppers full of product are stored until they find a buyer.  The plants that make pellets need to keep a fairly steady rate of production so it's easier to "warehouse" it in the cars because every time you handle it you risk contamination.

Pellets come in a lot of color variations, but most pellets used for packaging are high-density polyethylene and polypropylene.  Odds are good your plant would get both, so you need unloading spots for at least two cars.  Odds are also good that a couple more cars would be waiting "off-spot", either on the same spur or anyplace the railroad holds off-spots.  Local yards often have a dedicated track for holding off-spots.

One other thing I noticed in Mr. Husman's photo: there's only three rib-side pellet hoppers visible.  You do the math.  I have one each of the Overland Pullman rib-side and Richmond "mini skirt".  Don't need any more....

Scott Chatfield

Pellet unloading

The places I’ve seen that receive a variety of plastic pellets have several pipes, in parallel, so they can pull pretty pretty much any car to any silo/storage bin they want.  Just have to hook the hose up to the right pipe.  Some places seem to unload fast, but some (including Micron Plastics I posted the photo link to earlier) used the cars as storage - they’d stay there a week or two or more as they pulled small batches of pellets out at a time.  The order the cars got released in seemed to be fairly random, and there were respots - new cars were on the switch end of the spur, respots ended up at the end even if they didn’t start there.

A pellet transload operation I got some tidbits on from a railroad employee had 3 tracks that could hold about 7 cars each.  When cars were delivered they’d get stuffed in anywhere they fit.  As customers wanted one or another type/color of pellet, trucks would come in and vacuum out the appropriate pellets from the appropriate car.  So the other the cars got emptied was pretty random.  So which cars got pulled were pretty random.  Apparently just a few cars in and out per week, but since the pulls were from some random spot still more switching than you’d think.  Not really “spots”, but an interesting variation in switching from something like a warehouse with clearly assigned spots.

Plastic Pellet unloading

One thing about plastic pellets is that they are not all the same. Depending on what kind of plastic product the company is producing, especially when it comes to some type of container with a lid. Think of a milk jug. The hard cap is made from one type whereas the body of the container is made from another.

In many industries that receive plastic pellets, you will have individual car spots. And each of these spots will often have piping going to a specific silo or part of the plant where that particular grade of plastic pellet is stored or used. Some cars may remain at an industry for a couple of months before it is actually unloaded where others may only stay for a couple of weeks or even less.

Atlas makes a 5800 cu cap car that can still be seen in service today. Most of the 5701 cars are being replaced by the larger 6400 cu cap cars. I’ve been pushing for someone like Scale Trains or Exact Rail to produce the 6400 cu car but haven’t had any luck. It’s too bad because there are literally thousands of these cars made by Trinity and NSC rolling all over North America as I’m typing this.

Here is a shot of one of my industries in the background that has five car spots. Four are for plastic pellets and one for tank cars. It’s fun to switch this small industry out because it’s not a basic pull and spot. The industry orders cars by number and provides instructions for which spot the car must be placed. Not only is this realistic, but requires more time and can make switching operations longer and more enjoyable.

Tim G

Spots vs Pipes

Interesting about the specific spots Tim.  I know at least some of the operations around here that get different types of pellets don’t care about order, I guess I assumed most were like that.  I wonder what the deciding factor is?  Also makes me wonder about a couple local places I don’t know for sure work, but just assumed they were like the ones I do know about.

There’s always more stuff to learn in this hobby!

The answer is all of the above

How pellet hoppers are spotted and emptied depends on how the material handling system of the factory is set up.  The permutations are many.  Some plants use more varieties of pellets than they have spots for, or vacuum lines for.  They might have the railroad pull a partly empty car and replace it with another car from off-spot.  The partly empty then goes to the off-spot track, wherever that is, and is brought back later.  Paying the railroad a switching charge is cheaper than building a storage system that can hold all the varieties they need over time.

There are two plastics plants on the libe I model.  They're about a half mile apart in the real world.  One makes plastic films and lightweight containers for food packaging.  Almost everything they make is clear or translucent, so they only need four types of plastic.  And they _always_ have four pellet hoppers on hand, and usually an equal number waiting off-spot.  When a car is emptied it is replaced asap, but they are not switched every day.

The other customer in the time I model (late '80s into the early '90s) made large plastic containers and pipe.  They also had room for four cars on two tracks, then added more vacuum pipes along the switch lead so they could unload two more cars.  They usually also had six to ten cars off-spot.  Around 2000 they added a bunch more products to their line so they needed more pellet hoppers at all times.  They rebuilt the tracks so now they have one long track with spots for 14 cars, and keep 20 or more off-spot.  And they will often have partly emptied cars pulled and replaced.  They are switched almost every day.

Since I only had room for one of them, I chose the one that gets switched every day.

Scott Chatfield

Partly empty shuffle

The world of plastic pellet industries is even more interesting than I thought.

Scott, the industry that has the 14 spot track with 20+ off spots - do you know how their pipes are set up?  Is it 14 pipes each to a specific spot, or 7 pipes each cover 2 spots, or some number of pipes running the whole length, or ...?  I assume the reason they need partially unloaded cars pulled and replaced with an off spot is because they have less pipes than the number of pellet types they use?

I’m very curious because I’m modeling a plastic pellet distributor based on a prototype industry I’ve seen, but don’t have any solid details on how the switching works.  They have 2 tracks that can hold 4 cars each and clear the switch, and I’ve seen I think it was 6 cars on one of the tracks - I assume 2 off spots.  I think they can connect the hoses to any of the 4 cars on either track, but I don’t know how many pipes they have going around to the dozen (+?) silos of various sizes around the corner of the building from the tracks.  I’m wondering now if they do any of that swap out a partially unloaded car for an off-spot stuff.  Or if I can reasonably do that on my model.

I don't know

I don't have that answer Ken, because I didn't plan on modeling these industries years ago when I was doing work in that area, so I didn't do enough research.  I was going to model the mainline south of there  to a different city.  Time moves on and I finally decide to build a switching layout and that area was the best fit to my basement whose thick roof I've lived in far longer than I planned.  And since I'm modeling 25-30 years ago I haven't really dug into the details of their current arrangement.

I do know that when they shuffle cars it's because they need a different type of pellet than is in any of the 13 or 14 cars they have hooked up right now.  A few off-spot cars are kept on their spur beyond the last hook up, but most are kept on a track the railroad built for the purpose about 15-20 years ago.  It's about a mile away.

And I don't know how often they shuffle cars.  I will probably do it more often than they do just because it adds interest to the ops.  Like Tim G wrote, it's not just a simple pull and drop, which is far far far too common on model railroads.

Scott Chatfield

Switching charges

Every time the customer orders the car off spot, its a $50-75 switching charge and every time the customer orders the car back on spot, its a $50-75 switching charge (assuming its a class 1 railroad doing the switching.)  So swapping car A for car B, then finishing A and going back to B will cost the industry $250-375.

A car gets one free spot.  If the car's first spot goes to an unloading spot, that's free, if the car's first spot goes to off spot track, that's free.  Any moves after that are chargeable, except for the empty pull.  Any move for one spot to another is chargeable, any move form a spot to off spot is chargeable, any move from off spot to a spot is chargeable.

If the industry has its own car mover and its own tracks (including a lead inside the plant with enough room to the switching, where it doesn't have to go past the "fence") or if its a short line that's ok with leaving the money on the table just to get the basic revenue, or the class 1 switch crew doesn't report the switch moves, then they won't be charged for the switching.

For a model railroad that really doesn't mean that much because nobody is sending anybody a bill, except that while there are those industries that are set up to move cars around, there are way more industries that just spot a car once or make one move from off spot to spot because of the switching charges.

Interesting discussion!

Based on what i read here, i was wondering and i would like to double check if cars spotted in parallel tracks can be all unloaded (longer hoses used for the cars spotted on the outer tracks?).

Tim (Garland), very nice scene there! I was wondering what is the purpose of the tank car...i suppose this is a plastics molding factory?

Sometimes...

Hi all,

with my production planner hat on..

Sometimes the cost of not getting a switch done far outweighs the costs of the switch. What do I mean by that??

If things go "according to plan", then this shouldn't happen. But sometimes there will be a red-hot order that "absolutely-positively" has to be made "right now" that forces a change in the production plan at your model plastics plant. The costs of not making that red-hot order can far outweigh the cost of the switch in terms of the cost of lost production at the customer site, loss of future orders, non-delivery penalties, etc. Previously on another thread I wrote:

Now imagine that your model plastics plant is stamping out car fenders for a car maker, like in my example above. Unbeknown to you, the car maker's sales team have sold a "high priority" fleet order of 300 vehicles that require red bumpers and you are currently stamping out an order of 1000 white ones as per the agreed make priority with that car maker. When the red cars jump the priority queue and are scheduled for the production line earlier than you were planning to stamp out their next 1000 red bumpers order...and they only have 50 red bumpers in their warehouse.. The panic really sets in when everything else for the red cars is going to make it the assembly plant in time for those "urgent" red cars apart from the red bumpers that your plastics factory haven't even started to make yet... Against the cost of stopping their assembly line to wait for the red bumpers or the cost of manually fitting a couple of hundred red bumpers out in the yard after the cars have left the assembly line, the cost of a switch or two to get the right red pellets into the injection machine ASAP is really very small beer indeed. 

No it's not ideal, but sometimes it's cheaper to wear the cost of the switch, or even the cost of 2 or 3 car moves..if the cost of "not getting it done" are sky high.  Sometimes that "urgent" extra switch or two isn't even your fault, but you're picking up the bill and wearing out favours.  

Old photos

An interesting discussion indeed!

On the switching fees Dave - does it make a difference if the off spot storage is right next to the industry, or a mile away?  (I’d guess not based on what you wrote, but maybe it affects wether the crew might overlook reporting it?)

Nice example John.

John, interesting detail about the storage track a mile away.  It’s got me thinking about a particular short double ended track near the prototype industry I’m thinking about which sometimes has cars sitting on it, but since it’s also very near a yard I had just assumed those were cars stashed out of the way.  I think it’s time to go dig through my old photos and see exactly what cars I may have caught sitting there - perhaps it’s being used as a storage track.

AEP Industries

Thanks for the complement Yannis. You can see more of my Seaboard Central on my Seaboard Central Facebook page and YouTube channel. I have some photos and videos showing the industry being switched. There’s also an operating session filmed of the layout on Thomas Klimoski’s YouTube channel.

AEP receives plastic pellets and tank cars filled with Soybean Oil and some with chemical product. This industry makes plastic wrap for the food industry. 

Tim Garland 

Switching

FYI : the vast majority of the plastic pellets are either white or clear.  Colors are added  after the pellets are out of the car.  The better scenario is they are molding dashboards, then have to switch to bumpers (different grades of plastic).

Normally what the people who do switch around the cars are doing is avoiding the cost of adding storage silos at their plant.  The plant uses 5 grades of plastic, so has 5 storage silos.  They then expand their product line to offer products that use 7 grades of plastic, but they don't want to spend $100,000 on two new silos and piping.  So they use the  railcars as "storage" for the two additional grades.  Private cars on privates tracks don't accrue demurrage. Private cars not moving and cranking up mileage don't accrue car hire.  It then becomes an issue between the car lessor and the industry on how long they keep they cars.  Since those types of cars are reeeeeeeaaaaaaaalllllly low utilization (one, two, maybe three, loadings per year) it may not be a big deal.  Or, because its such a low turnover the chemical manufacturer might be hot to get the empties beck to load to keep the chemical plant in production.

That's something that modelers don't realize that in many cases on the railroad, some empties are as hot or in many cases hotter than loads.  Back when coal was king, empty unit coal trains were way hotter than loaded unit coal trains.  Woe be the person that delayed empty coal trains.  Chemical empties are often hotter than loaded cars and auto parts empties can be as hot as loads.

If somebody wanted a really heavy duty switching operation, they could model a SIT yard.  Ten tracks that hold a dozen cars and a lead that's 15-20 cars long.  Put 100 virtually identical covered hoppers in the yard.  Then choose 5-10 cars at random to be released.  The night switcher then digs through the yard and cherry picks the 5-10 pull cars out of the 100 cars in the yard.  The rest of the cars stay.  After pulling the empties the switcher puts 5-10 new loaded cars into the yard where ever there is room.  No attempt is made to "organize" the cars in the yard by owner, car number or grade of commodity.  There is no FIFO on the cars.  While the actual selection of cars is very intentional, from the standpoint of the switch engine, the selection of pulls appears totally random.

Storage track

Two ways industries get cars.  "Spot on arrival" and "order in".  Spot on arrival the cars are spotted when they show up, typically at "standard" locations.  Wood chips to the dump track, boxcars to the loading dock.  Typically those type industries don't have "detail" spots.  The railroad spots a car and if there is any detail movement of material, the industry takes care of it after the commodity is out of the car.  The rubber components are generically spotted at the dock and a forklift carries the racks of rubber components to the rubber component machine, vs.  rubber components go to door 6.

For order in, the cars are billed to generic location (track), held on that track, and the industry orders in specific car numbers as needed, which may or may not go to a specific spot. 

Some cars may be spotted on arrival, some may be ordered in.  The switching order could be left in a bill box or from the shipping foreman that the conductor gets when he arrives at the industry or it could be give to the agent/customer service center and the conductor might have it before he gets to the industry.  If the storage track is not in the immediate vicinity of the industry, then they will have to provide a switch list to the railroad before the local comes on duty so they will have the list to dig out the spotters when they get to the storage track in order to bring them to the industry to spot.

That can cause an order in industry to look like a spot on arrival, because the digging out of spotters happens "off layout".  If you are modeling just a single industrial lead or a single station, and the spotters are held at another station/track or yard then the switching of spotters and the "ordering in" process will have already happened before your layout is in the picture.  The local arrives with the exact cars they need and just spots everything.

Spot on arrival is a more modern approach.  My 1903 layout will be almost all spot on arrival and off spots will be mostly because the track is full.  If I was modeling 2003, it would be more common that I would have CP cars (constructively placed) that were being held off spot until being ordered in. 

....

You are more than welcome and thanks Tim for the reply, ( I suppose the oil you mentioned in the tank car is used in the molding process?).

Thanks to the OP for starting up the interesting topic! The discussion on car spotting and unloading is very useful!

Inter-plant switching

Like Dave mentioned many customers who receive covered hoppers of plastic pellets and tank cars loaded with chemical products will end up being shipped to an industry with specific car spots. And since these cars are always private marked cars ending in X, they will not be charged demurrage fees as soon as they are shown on the customers tracks. Although they will be assessed the charges while remaining in the local railroad serving yard waiting placement until they are ordered by the customer.  

Sometimes the customers trackage will include either a long lead or another track that can be used to store extra cars in order to get them off demurrage. These cars can then be requested to be moved from storage to a specific spot or from a spot location back to storage. When this work is performed by the railroad the customer will be assessed an inter-plant switch charge. And that charge can vary from railroad to railroad.

Another charge that private cars can receive is a tariff charge implemented by a number of class one railroads if the private car (other than a tank car) has not been released within a specific time from the date of the previous loaded waybill. On NS it is 180 days. This same charge can occur if the empty railcar makes a back-to-back empty move. When I worked in railcar management I did a Six Sigma project on this very subject.

Railroad switching in the modern era can be interesting and maybe that’s why switching layouts have become more popular lately. 

Tim G

Intra-plant switching

Moving cars around inside a plant is INTRA plant switching as opposed to INTER plant switching.  I know, picky, picky, but if anybody wants to Google it, they'll have to use "intra" plant to get the results they want.

Much of this stuff is all paper trail stuff that the modeler will never see or even want to see.  Where it shows up depends on how far up the food chain the modeler choses to model.

That harks back to the discussions on the size of the layout.  The narrower the geographic focus of the layout, the fewer things get included because they happen up the food chain.  For example, if the order in cars are stored at the yard and all I model is three blocks of the industrial lead, then I would never see that the spot cars in my train were actually cherry picked from 10 cars stored at the yard.

Also many of these things happen and aren't particularly obvious to the modeler, they don't result in an identifiable, modelable, option.  The decision to use the covered hoppers for storage rather than build storage silos isn't really modelable, it just falls out as a switch move with no real difference than any other switch move.