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Operations |
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Operations ConceptAlthough the layout isn't far enough along to "operate", here is the basic concept of operation - some from the prototype, some reflecting the model: (Lots of text follows) Overview The Duluth, Missabe and Iron Range Railway exists primarily to transport iron ore products. Ore is moved from mines to Great Lakes Boats at Duluth for eventual delivery to steel mills. Passenger and miscellaneous freight movements are secondary to the movement of ore. The logistical challenge in the movement of ore is to provide enough empty cars to all mines to accommodate their loadings, to collect and move all loads to Proctor and to provide loads to the Dock to load empty Boats. Logistics is further complicated by the fact that mines produce, and the mills order, different grades of ore. To meet mill orders, grades from a variety of mines must often be mixed at the dock when being loaded into the Boats. Iron Ore Grades Iron ore does not occur naturally in a pure state, but can include a variety of other trace elements. Some trace elements are desirable in steel making, some are not. In real life, ore quality and composition varies infinitely, and the grade of ore from a single mine can vary depending on what part of the mine the ore came from. For modeling purposes, there will be three arbitrary grades, 1, 2, and 3. Each grade will be represented by a different color ore load, yellow, red and purple in color. Mines Mines produce loads of ore by loading empty cars provided by the DM&IR. Generally, the empties are moved through load-out pockets by gravity or a car puller. Complex mining operations sometimes “go down” owing to equipment failure, but also load more cars. Simple mines produce fewer loads, but are less prone to downtime. After loading, the ore is sampled to determine its composition. This composition is relayed to the mine owners and the railroad. Each mine produces ore of a specified grade, and at a specified rate (cars per day). Each mine also has a likelihood of failure, that is, a probability that they will break down and not operate on a given day. Duluth Ore Docks The ore docks have four tracks on them. Two tracks fill pockets on one side of the dock, two on the other. There is a double crossover at the head of the dock to allow dock and Hill engines to tie onto different cuts of cars. Each ore dock has pockets on 12-foot centers. Each pocket can hold four carloads of ore. Ore grades can be mixed as they are dumped into the pockets to meet Boat requirements, but to achieve the best flow out of the pocket, the first load of ore should be a coarse ore dumped from the inner track. If needed, a string of cars can be held on top of the dock to be dumped when the Boat arrives, effectively allowing five carloads per pocket. A single dock can handle 4 to 6 Boats, depending on Boat length, but the arrival of all at once is unlikely. The cars and the Boat hatches are on 24-foot centers. Thus, every other pocket will be discharged into a Boat, the Boat winched ahead or back, and the intermediate pockets discharged. Prior to the arrival of a Boat, the Ore Dock designates which pockets are allocated for the Boat, notifies Proctor of the ore composition required, and begins filling the pockets from the Hill ore trains. Ore Boats The composition of the ore ordered by the mills changes depending on the type of steel being produced. When a Boat arrives, it is to be filled with ore of a composition specified by the mill. The composition of ore grades for Boat orders is from 6 to 13, inclusive. For higher grade orders, this will require five cars per pocket. Some combination of the grades of four or five carloads of ore must total exactly the value of the Boat order. Proctor Yard Ore Sorting Proctor Yard is the main yard on the DM&IR. It handles arrivals and departures of ore trains and miscellaneous freight, and services all locomotives and cars. Sorting of ore loads is by grade, sorting of miscellaneous freight is by destination. Empty ore cars generally do not need to be sorted, but need only be provided in appropriate quantities for northbound Ore Extras. By the time a carload of ore reaches Proctor, the composition of its ore is known. As the cars arrive, they are classified onto tracks by grade. When Hill ore trains are ordered, they are made of loads a specific composition or ore to satisfy Boat orders at the Ore Dock. Ore Processing Plants Large ore processing plants, such as Rouchleau or Hull-Rust Concentrator produce many loads per shift. They generally are served by dedicated locomotives from either the mining company or the DM&IR to spot and pull empties and loads. Mine Locals Mine Locals originate at major north-end yards and exist to deliver empties to the mines, and to pull loads. They do not generally assist in load-out efforts. Cross-Range Trains Cross-Range trains originate at major north-end yards and exist to move large cuts of cars from one north-end yard to another to balance the movement of cars to and from the north end. Ore Extra Trains Ore Extras generally originate from either Proctor or Two Harbors, and exist to bring empties to major north-end yards, and return loads from those major north-end yards to Proctor or Two Harbors. A train that “dies” on hours of service will be called where it died. Generally, an Ore Extra originates and returns to the same yard on its hours of service, and runs to only one north-end yard. An Ore Extra could be directed to drop off or pick up cars from more than one major yard. Hill Ore Trains Generally, the Hill Ore trains originate in Proctor and exist to bring loads to the Ore Dock, and to bring empties back from the Ore Dock. A Hill Ore train may be directed to handle miscellaneous freight to and from Missabe Junction. Steam locomotives in Hill Ore service must back down the hill to protect against crown sheet failure. In Hill Ore service, the down-bound caboose is cut off at 40th avenue, and is stopped by the handbrake while still on the hill and short of the next crossover. The up-bound train pulls past it. The crossover is lined for the caboose, the handbrake is released, and the caboose drifts onto the other track and again brakes. The up-bound Hill Ore then eases backward to couple onto the caboose. The train then proceeds up the hill to Proctor. Dock Switcher The Dock engine exists to spot arriving ore cars over the appropriate pockets, and to assemble empties for pickup by the Hill Ore train. Storage Tracks Three storage tracks are behind the Ore Dock and represent Missabe Junction when entering from the Duluth Ore Dock, and Two Harbors/Ely when entering from Biwabik Miscellaneous freight can logically travel both ways through this storage yard. Loaded ore can logically travel to Missabe Junction storage and arrive at Biwabik from Ely storage. Loads can logically travel to Two Harbors storage from Biwabik, but must be emptied before returning from Missabe Junction storage. Empties would not logically run to Missabe Junction storage, but could logically arrive from Two Harbors storage. Generating Orders An Access database was built to create empty car orders for shippers and ore loads for Boats. Every shipper has a min and max number of empties to be ordered per day, a likelihood of failure value (likelihood that they will not order on a given day), and if the shipper is a mine or ore processing plant, they have an ore grade of 1, 2 or 3. Each boat has a lake cycle time (how long until they return for another load), and an ore grade of between 6 and 13 (see Ore Boats above). There are a number of Boats in the database, although there is only one model Boat on the layout. The other Boats are theoretical arrivals, since the Missabe will get the pockets loaded ahead of the actual boat arrivals. Every time empty car orders are generated, the orders are grouped for each north-end Agency (an Agent is present) yard, and for Proctor. Mine Block waybills should be used to forward the correct number of empty cars to the correct mines.
Example: Virginia will see all the orders for empties for the Rouchleau, and surrounding mines, as well as any orders for pulp and lumber flats, etc. Proctor will get a summary of all ore empties needed so that they can plan Extras. Virginia will attempt to fill its daily orders from cars on hand. Any shortage will be requested from Proctor.
Before a day starts, all the empties presently at all mines should be loaded. When new empties are delivered, any loads should be pulled. Generally, all ore loads are assumed to be billed to Proctor, and waybills are not used. Thus, ore loads pulled from a mine by a Local will go to the Local’s home north-end yard for furtherance to Proctor. |