The Track Dept. informed us that the main interlocking will be out of service for the rest of the morning at least...  Perhaps it would be a good time to take the yard vehicle and give the new conductor trainee a tour of the mill.

  We'll start with the woodlot.

   Pulpwood varieties are chosen carefully according to the specific paper product in production. Softwoods for example, are valued for their long fibers which are required when producing coated papers.  Other woods are sourced for the production of cardboard etc...

 Most of the pulpwood has been chipped at an offsite mill from where it is trucked and sorted in the woodlot.  Some varieties such as Aspen however, arrive as raw logs and are milled on-site.

  While they rarely ship wood-chips by rail, we do occasionally spot log cars to the aptly named "1-Log" track.  We also get gondolas with scrap ties.  The ties are chipped and mixed with bark shavings and other waste products and sent to the Recovery Boiler.

   Paper mills are incredibly energy intensive.  All the mills energy needs therefore are produced on-site at the Recovery Boiler.  Power is generated by wood waste and chemical by-products created by the pulping process.  Occasionally, the mill will order a few loads of coal to ensure the power needs are always met.  These loads need to be spotted on track 55.

  Back at the woodlot, a specific mix of wood chips will be loaded onto the conveyor for transport to the Kraft Mill where it will be turned into pulp.

   The woodchips will be mixed with water and soaked in big tanks until they are soft to begin the pulping process.

  In mills using chemical pulp processes, Sodium Hydroxide is the key ingredient.  This is provided in hazmat tank cars and spotted to track 19.

 The softened wood chips are then mixed with the Sodium Hydroxide in the digester.  The chemicals cause the cellulose in the wood fibers to separate into raw pulp and a by-product called "Black Liquor".

 The Black Liquor is pumped to the Recovery Boiler where it will be recycled into energy.  However, new research suggests the by-product may have other uses as a source for carbon-fiber materials.

 The raw pulp is then sent to the main building where it is dried and either packaged and shipped to other mills as "Kraft Pulp" or mixed with various additives to make a finished product in the paper machine.

  While Kraft Pulp and unbleached products such as cardboard don't require bleaching, most other products require whitening.  This process requires some form of chlorine gas, which can be extremely hazardous when produced and shipped in mass quantities.  In the past, such shipments were to blame for some of the most deadly rail disasters. More recently, much of the danger has been mitigated by shipping chlorine in a much less volatile solid form known as Sodium Chlorate.  While still considered a hazmat, Chlorate cars are spotted to track 17 in unpressurized hoppers.  Here, the bleaching chemicals will be manufactured on-site.

 Additives will make up the final stage of papermaking.  Here, the rolls of paper will be coated with various grades of starch, latex and/or clay to provide each product with its unique quality.  Clay cars might look all the same on a waybill, but where the mill traffic annex is concerned, each car has a specific type of clay which can make or break the specific needs of each paper in production. Clay cars shipped from Omya in Vermont will usually be some form of Limestone, while cars shipped from Imery's will be loaded with some form of Kaolin. 

The mill requires the clays and other additives be spotted in a very specific order.  Starch cars for example, almost always ship in pressure-flo hopper cars and therefore must always go on the bunter since the hose can't reach outside the shed.  Latex cars tend to only be used when the mill is tooled either for cardboard or food grade wrapper production. The first task of every morning is to work out which additives the mill wants so we can dig them out in the correct order. 

 Finally, we come to shipping!  Track 15 shipping can fit 3 regular or F-Plate boxcars. (Note: Most prototype mills will actually have 3-4 shipping tracks).

  Except for when the pulp mill is retooling and the mill orders loads of Kraft Pulp, switching this track should be as simple as pulling the loads and spotting the empties.  Except for when it isn't...

   Ideally, the shipping dept. will have all the cars unloaded by the time you make the switch.  All too often however, they'll only have the rear car unloaded and they'll insist you pull the track and set back the other empties.  The big 60' double door boxcars are another headache as they only allow enough room for one other regular and they can only be spotted in a very specific place.  Otherwise the loaders can't access the doors.

  The mill switcher's nightmare comes about when the traffic annex makes it their business to nitpick exactly which empty boxcars they want us to dig out, no matter how many switching moves it will add.  Less scrupulous shipping agents for example, will purposely pick cars that take the longest to dig out in the hopes of saving money on a demurrage agreement.  

  Generally speaking however, this nightmare can largely be avoided by ensuring we always give them F-Plates and High Caps (e.g High Capacity< 90,000 ibs) before any regulars.

   And thats the Mill!  Once the tracks are back in service we'll go over how we actually go about lining up these moves before switching even starts!