Structures Update

I made some progress on the layout over the holidays, so I’ll post a few updates to bring things up date. Check out the photo for some details.


In this scene, you’ll see two structures that have replaced stand-in shells. In the centre of the image, the concrete building is the powerhouse. It’s not finished, but it took a great number of hours to get it to this point. I feel that it’s far enough along to give a good impression of how this scene will proceed. This is the powerhouse building, loosely approximated from aerial photos of the plant. It is currently sporting the base colour that use for approximating concrete structures. It’s entirely scratch built, except for the shed building in front of it in grey primer. That building uses a Tichy kit for the side wall. I’ll scratch build the end wall and roof. This will be the enclosed building into which hopper cars are spotted for unloading of coal into the storage silo.

Behind that building is a concrete structure with brick curtain walls. This is the end of a building in the area of the paper machine, where bulk solids are delivered by boxcar. This building is finished except for the final details and clutter. Here’s a photo featuring this structure.


The building to the right is a mock-up/core of the next structure on my to-do list. Also in this photo, you’ll see that I’ve painted the facia. Next time, I’ll post more details about the facia and valance.

Pulp Making and Bleaching


The list of raw materials arriving at a paper mill is exhaustive, and that list varies greatly depending on the time period, the type of product being made, the geographical location of the mill, and the type of process being used. My research leads me to believe that it’s not possible to compile a list of raw materials that would be correct for every paper mill because of the range of chemical options available to accomplish similar things.

I’ve been continuing to gather information as I proceed with the construction of my layout, all the while refining the details of exactly how the plant operated. Having arrived at the point that I need to build up a fleet of freight cars, I’m examining the flow of raw material more closely than I did in the planning stages. Here’s a basic outline of my limited knowledge. I think it will be obvious as you read, but I’d like to make it abundantly clear that this is my best summary of an extremely complicated manufacturing process. I’m the farthest thing from an authority on how paper is made (or chemistry for that matter), and I’m actually not terribly concerned with the exact details. I’d like to know just enough to make the traffic flow at my model paper plant seem correct. In the process of doing that, it helps to have a basic idea what’s in all of those freight cars. I welcome any information, particularly with respect to the chemistry involved with making paper in the 70s.

Here are the basic steps to arrive at pulp that can be put into the paper machine.


This is the basic material from which paper is manufactured, so it might seem obvious. But not all paper mills use woodchips as their starting point. Some buy pulp from a pulp mill and do the rest of the work on site. My mill received woodchips from central and northern Ontario from about 1965 until the time it ceased operating in the early-mid ’70s. I’m modelling the Penn Central era, so that fact fits nicely with my needs.

Apparently, the woodchips were shipped in unmodified boxcars. The woodchips were unloaded from the boxcars and stockpiled at the site of the former log yard. A conveyor took the woodchips to the digester. I’m not modelling any of that process on my layout. Instead, I use one track of hidden staging that represents the unloading of boxcars. I’ve accommodated for a maximum of ten 40′ boxcars to be staged just off the layout, either loaded and awaiting unloading, or empty and awaiting being taken away.


A digester is used to transform woodchips into pulp. It’s basically a tall skinny pressure vessel in which wood chips or other raw materials are cooked into a pulp. Modern digesters operate in a continuous feed manner, but I’m guessing that mine operated in a batch-by-batch manner. Aerial photos show only one obvious digester, so unless there was another one in the plant that I can’t see in my photos, I’m assuming they did specific batches and then stored the pulp in a large storage tank until they had enough to process into paper. A digester looks like a tower anywhere from 100 to 200 feet tall and about 15 feet in diameter.  The cooking process requires a supply of woodchips, cooking liquors, steam, and a few other chemicals to manage the Ph of the pulp.

I’m not including a model of he actual digester, which was buried behind a maze of tanks and metal buildings. But I’m modelling the buildings and facilities where the materials were stored and unloaded from railcars. Cooking liquors arrive in tank cars, and some of the minerals (like paper makers’ alum) arrive in covered hoppers or paletted in boxcars.


The process of cooking wood into pulp in the digester produces a by-product called black liquor, which contains more than half of the energy content of the wood. A recovery boiler is used to extract white liquor out of the black liquor, which ends up being waste. White liquor is used again in the pulping process (ie. fed back into the digester).

The recovery boiler also produces liquid lignin as result of the extraction of white liquor. Liquid lignin can be burned to produce steam which can be used in steam-hungry processes (like the digester and recovery boiler). You should start to notice that a paper plant runs the pulp through and the pulp extracts through many cycles where the extracts are refined to be used in the original pulping process, and the by-products are scrubbed clean and put back into the process in one form or another.

Liquid lignin can be turned into solid lignin, which seems to be some kind of salable by-product. I don’t know what solid lignin is or what it’s used for, so I’m not sure how (or if) it leaves the plant. But I do know that sulfuric acid and water are needed to transform liquid lignin to solid lignin. Sulfuric acid will show up at the paper plant in tank cars.

BLEACH PLANT – This is a facility designed to whiten, to whatever degree necessary, the pulp that is created in the digester. This part of the operation is comprised of washers, chemical preparation units, pumps, tanks, piping, etc., all of which is designed as part of a system for bleaching pulp. Chemicals in this process are fairly nasty, and much of this particular operation produces harmful dioxin which destroys every living thing its path. Much of the process of bleaching changed after Love Canal, which I suspect was the reason that the plant I’m modelling closed.

This aspect of the mill is represented on my layout by some smaller buildings, tanks, and one very large metal-clad building. This step in the process uses chemicals such as chlorine, chlorine dioxide, sodium hydroxide, hydrogen peroxide, sodium hypochlorite, oxygen, ozone, and other stuff I’m not yet familiar with. Bleaching involves several stages, each one followed by washing to remove colour and chemicals from the previous stage. There are flocculants used to get impurities to stick together and therefore make them easier to remove from the pulp. Flocculants are typically things like calcium oxide, aluminum sulfate, calcium hyrdoxide, and ferrous sulfates. I suspect that all or most of these things came to the plant by rail. There were plenty of chemical processing factories within 40 miles of this paper mill. In fact, the interchange with Niagara Junction Railway, which served Hooker Chemicals in Niagara Falls NY is about 8 miles away by rail. I think most of this stuff came into the plant in tank cars, but it’s possible that some of it came in granular or powder form in covered hoppers or on palettes in boxcars. I’ll make some assumptions until I learn otherwise.

Freight Car Movements (So Far)

I’ve compiled a list of the materials needed to make bleached pulp for input into the paper making machine. I’ll look at the next step in the paper making process in a future post. I have no idea whether all of these things were necessary, or if some of these things are substitutes for others. But just for fun, here’s a list of commodities and the freight car most likely to have delivered them to my paper mill. My knowledge of industrial chemicals is nearly zero, so if anyone can correct any errors with respect to the purpose of the chemical or the method by which it would have been shipped in the early 1970s, please feel free to enlighten me. Also, with the exception of the woodchips, I’m not completely clear on where these chemicals might originate. Help there would be appreciated as well.

Here’s the list (I’ve been editing this list as I learn more about the various chemicals and the processes)

woodchips – very old boxcars

white liquor – tank cars ?? (could have been created on site using water, sodium hydroxide and sodium sulfide… see comments)

chlorine – tank cars

chlorine dioxide –  tank cars

sodium hydroxide, sodium sulfide – barrels in boxcars

hydrogen peroxide – tank cars

sodium hypochlorite – tank cars

oxygen – cryogenic tank cars or trucks oxygen delignification appears to be a process created after my era (see comments)

ozone – ?  the use of ozone for bleaching appears to be a process created after my era (see comments)

sulfuric acid – tank cars

calcium oxide – covered hoppers or boxcars

aluminum sulfate – covered hoppers or boxcars

calcium hyrdoxide – covered hoppers or boxcars

ferrous sulfates – covered hoppers or boxcars

Black liquor could leave the plant in drums to be sold for the production of turpentine.

Next stop: the paper machine.

In a future post, I’ll try to outline the process whereby pulp is spread out on a continuous belt, and then dried, pressed, and stretched into a continuous roll of finished paper. There are a couple of important raw materials that go into that process as well, so I’ll address those at that time.

Feeding Coal into a Paper Plant

In my post from yesterday, I presented the first draft of the diagram that operators of my layout will use to help them determine which cars are moved to and from each car spot. That post generated a question about the purpose of the spots and the commodities, so I’ll start to answer that with a description of how the plant manages the production of energy. I’ve added some colour to the diagram to help clarify things and to give some indication of how the plant operates.

International Paper Schematic

It takes a great deal of energy to make paper, and the International Paper plant at North Tonawanda had its own powerhouse fueled by coal. During peak production times, the plant consumed as much as 150 tons of coal per day. That amounts to average flow of two to three hopper cars daily, depending on the size of freight car being used. I don’t have all of the details of how coal was delivered and unloaded at the plant I’m modelling, but I’m making some informed guesses to come up with something plausible.

I do know that coal was stockpiled at the edge of the property near the warehouse/shipping area, so that’s what I’ve modelled. There was also a 100 ton silo at the powerhouse, so in my estimation, they would make sure the silo is always more than half full to ensure there are no interruptions in power supply. The powerhouse is shown in red in the diagram. The stockpile is adjacent to the “coal track” at the bottom right.

The stockpile of coal assures that fluctuations in the supply of coal can be managed. Coal can arrive at the stockpile in quantities larger than the daily consumption for a number of operating sessions, and there also needn’t be any delivery of coal for a few “days.” This allows for a great deal of variation in the flow of traffic. The plant also uses a hopper to shuttle the coal from the stockpile to the powerhouse. To accomplish this, they’re sure to keep one empty hopper car captive at all times, and the crew switching the plant might be assigned the task of shuttling a load or two between the bulk storage and the powerhouse. It’s also possible that some coal loads went directly into the powerhouse at the time they were delivered to the plant, though I imagine that would have happened less frequently than coal being delivered to the stockpile. Coal hoppers can be spotted at 27, 28, or 29. The unloader is at spot 29. The powerhouse is at spot 21.

I’ll put together a description of the other spots in a future post.


Track Diagram for International Paper

Large industries can be complex operations for railroad employees to sort out. From the ground, it can be difficult to figure out where cars are to be spotted, and the untrained may not be familiar with the fact that some moves cannot be made a certain times of the day. Employees learn on the job. They are trained by their peers on the idiosyncrasies of large industrial operations, and through repetition they learn how to make their side of the business work for the customer.

Operators on my layout won’t necessarily have the advantage of learning through frequent repetition, so I’ve drawn a schematic showing the layout of the various car spots and the buildings associated with them.

International Paper Schematic

The diagram represents all of the track and buildings on my layout, and assigns names and/or numbers to specific car spots. The diagram will have to be accompanied by some basic information like instructions to check in with customer’s freight coordinator for intra-plant shuttling and time-restricted moves when the train arrives at the plant, the capacity of certain tracks, permissible places to leave cars that are off-spot, use of bell and horn, speed restrictions, etc. I have some clear plastic clipboards for operators to use, and I plan to laminate these instructions to the back of the diagram with the switch list on company stationary on top.  This way, operators can flip the clipboard around to see the diagram.

Hopefully, I can find an example of a Penn Central or NYC diagram so I can make mine look like an official company document. Until then, this will have to suffice.

Building Cores Become Mock-Ups

I like to work in 3D when I plan. For instance, when I planned my layout, I had a basic notion of where the turnouts and track would go, and I moved templates around the benchwork until I came up with something that seemed reasonable. Then the buildings in my paper plant were mocked up with cardboard boxes. After that, I build styrene cores to hold the veneer of the finished models. In a few cases, it took a few attempts to get the proportions correct.

Once I felt that the proportions were correct, I set about finishing the structures, which I’ve started to do at one end of the layout. It would probably take another year of my spare time to finish up all of the structures on my layout, but given that all the track is functional, I’m feeling like it’s time to have some people over for operating sessions. I decided to try painting the structure cores in the approximate colour that the finished model will have. A trip to the local Canadian Tire store and I was set up with an assortment of spray cans.

I used a light grey primer on some metal structures, and a darker grey on others. I think those look good. The concrete buildings at the plant were painted in a tan colour, but the Krylon “camo light brown” that I bought looks more like a light olive colour. I think I’ll find a better colour and paint those again.

Regardless of my struggles with colour matching, the end result is that the painted building cores look more like coloured mock-ups now. While they completely lack any kind of detail whatsoever, they do serve to give an impression of what will eventually be built. I’m inclined to finish the scenery between the edge of the tracks and the structures in order to provide basic ground cover. Over the past month or so, I’ve posted some photos of the more completed areas of the layout. Here are some shots of the other end, now populated with painted building cores.


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