Loading Rack Simulation for Refinery and Petroleum Product Logistics

       Loading rack series:
       1 Loading Rack Simulation in Oil and Gas Logistics
       2 isLoadingPriorityOverSchedule in LoadingRack: Scheduling and Departure Logic
       3 Loading Rack Scheduling and Operating Strategies for Refinery Simulation
       4 Loading Rack Statistics for Refinery Simulation
       5 Loading Rack Control in Refinery Simulation
       6 Railway Wagon Loading Simulation: Train & Wagon Characteristics

       Solutions: Loading Rack Simulation in Oil and Gas Logistics

       Loading rack simulation for refinery logistics models the movement of finished petroleum products from refinery storage to railway tank cars under real operational constraints. In a refinery digital twin simulation, the loading rack connects continuous product flows with discrete railway operations such as train arrivals, wagon positioning, product loading, passportization, and train departure. A loading rack is therefore more than a product outlet. Its operation depends on product availability, loading capacity, railway schedules, wagon availability, and loading and certification times. These constraints determine how quickly finished products can be transferred from storage to transportation.
       In refinery simulation, these logistics constraints can also affect upstream production. Delayed train loading keeps products in storage, reducing available tank capacity and potentially limiting refinery operations. Loading rack simulation helps evaluate whether planned production volumes can actually be stored, loaded, and dispatched through the available logistics infrastructure.
Within the Anylogic-based Petroleum Refining Library, LoadingRack connects refinery storage with railway transportation and can be integrated with Accumulative Tank Farm and ShipmentNode to model the complete product shipment process.

       LoadingRack provides the main capabilities required to model petroleum product loading and dispatch in refinery logistics simulation

       Together, these capabilities allow LoadingRack to represent both detailed railway loading operations and simplified long-term product flows within refinery digital twins.

       The LoadingRack coordinates train arrivals, wagon supply, product loading, passportization, and wagon removal as a sequence of discrete operations connected to continuous petroleum product flows. The component is configured from database data, including loading rack infrastructure, train schedules, wagon assignments, product allocation, and initial residuals

       This workflow allows the LoadingRack to connect refinery storage, railway loading operations, and outbound product shipment within a single refinery logistics simulation model.

       LoadingRack supports several operating strategies, allowing the same simulation component to represent both detailed railway loading operations and simplified long-term product flows.

       These strategies can also be combined. For example, the model can use detailed Loading Priority during the scheduled period, account for tank car turnaround, and then switch to Direct Flow for long-term simulation.

See: isLoadingPriorityOverSchedule in LoadingRack: Scheduling and Departure Logic

       LoadingRack models both train-level and wagon-level loading characteristics. A train aggregates the capacity and loading state of its assigned wagons, while each wagon maintains its own capacity, product assignment, initial residuals, and current fill level. This allows the simulation to represent both complete train loading and product-specific loading for multi-product trains.

       These characteristics are also used by the LoadingRack control logic to evaluate loading progress and determine train departure conditions.

See: Railway Wagon Loading Simulation: Train & Wagon Characteristics

       LoadingRack provides runtime control over train processing, loading rates, and product volumes. This allows the simulation to respond to changing product availability, loading capacity, and operational conditions without changing the model structure.

       These controls can be combined with loading priorities, train schedules, wagon availability, and flow restrictions to model different refinery loading scenarios.

See: Loading Rack Control in Refinery Simulation

See: Loading Rack Statistics for Refinery Simulation

       LoadingRack supports a wide range of refinery logistics simulation and petroleum product dispatch scenarios, from detailed railway loading operations to long-term transportation analysis.
       Refinery product loading — models the loading of finished petroleum products from refinery storage into railway tank cars for shipment.
       Railway loading terminal simulation — models train arrivals, wagon positioning, product loading, passportization, and train dispatch.
       Refinery logistics simulation — evaluates how loading capacity, product availability, train schedules, and wagon availability affect product evacuation.
       Refinery digital twins — connects continuous refinery product flows with discrete railway transportation operations within an integrated simulation model.
       Production planning — evaluates whether planned product volumes can be stored, loaded, and dispatched through available loading and transportation infrastructure.
       Petroleum terminal logistics simulation — represents loading operations and transportation constraints at oil and gas terminals and other hydrocarbon logistics facilities.
       Long-term logistics simulation — uses simplified Direct Flow and post-schedule strategies when detailed train-by-train loading is not required.

This interactive model demonstrates two different LoadingRack operating algorithms for railway product loading and dispatch from refinery tank farms. The model compares Loading Over Schedule and Schedule Over Loading, showing how different departure policies affect train loading, product shipment, and wagon utilization.

Algorithm 1: Loading Over Schedule
       With Loading Over Schedule, train loading has priority over the scheduled departure time. A train departs when it is fully loaded or when its load ratio reaches 80% by default and the incoming product flow becomes 0.0 t/h. The model contains 7 trains scheduled for January 1–2. After the defined schedule is completed, train arrivals continue automatically using the same arrival rate, with a 10-hour interval between trains. The first route demonstrates railway loading of NGL and Propane from dedicated refinery tank farms. The model allows users to change the Passportization Load Limit and stop or resume individual product shipments to observe how product availability affects train loading and departure. Passportization: 4 h, Wagon removal: 2 h

Algorithm 2: Schedule Over Loading
       With Schedule Over Loading, the railway schedule has priority over loading completion. A train departs at its scheduled departure time regardless of its current load ratio. The second route demonstrates Butane railway shipment and tank car circulation. Only currently available wagons can be assigned to an incoming train. After loading and departure, wagons remain unavailable during their 10-day circulation period and are returned to the available fleet afterward. This scenario demonstrates how train scheduling and rolling-stock availability can affect refinery product dispatch even when sufficient product is available in the tank farm.

What the Model Demonstrates
       The two algorithms allow users to compare different refinery railway logistics strategies and observe their impact on:

• Train loading and departure
• Product availability
• Tank farm levels
• Railway wagon utilization
• Wagon circulation
• Passportization and wagon removal
• Shipment continuity and scheduling

       This makes the model useful for analyzing how LoadingRack scheduling strategies interact with refinery storage, product flows, and railway transportation constraints.

Important: This is not a video demonstration! It is a fully interactive digital twin running in AnyLogic Cloud. Feel free to experiment with the model by changing process parameters in real time.

       LoadingRack provides a flexible refinery logistics simulation framework for modeling railway product loading and petroleum product dispatch. By combining train scheduling, wagon loading, product flows, wagon turnaround, and operational constraints, it connects refinery storage with real transportation processes. The two operating algorithms — Loading Over Schedule and Schedule Over Loading — allow different train departure policies to be represented. Together with runtime controls, wagon circulation, and integration with tank farms, LoadingRack can be used to analyze shipment performance, loading capacity, railway utilization, and refinery logistics scenarios within an AnyLogic-based refinery digital twin.

1. What is LoadingRack used for?
LoadingRack is used to simulate railway loading and petroleum product dispatch from refinery storage to rail tank cars within refinery logistics and digital twin models.

2. What loading strategies does LoadingRack support?
LoadingRack supports Loading Priority, schedule-based operation, Direct Flow, Post-Schedule Operation, and Tank Car Turnaround strategies.

3. Can train departure be controlled by loading completion?
Yes. With Loading Priority, a train can remain at the loading rack until the required loading condition is reached.

4. Can a train depart according to its schedule regardless of its load?
Yes. With Schedule Over Loading, the train departs at its scheduled departure time regardless of its current load ratio.

5. Does LoadingRack support multi-product trains?
Yes. Individual wagons can be assigned to different products, while train-level capacity and loading values can be calculated for each product.

6. Can wagon circulation be modeled?
Yes. Tank Car Turnaround accounts for the time required for loaded wagons to return and become available for subsequent trains.

7. Can LoadingRack be integrated with a tank farm?
Yes. LoadingRack can connect refinery storage and railway loading operations, including integration with Accumulative Tank Farm and shipment planning.

8. Can loading operations be controlled during simulation?
Yes. The API provides runtime control of train processing, loading flow rates, product volumes, and passportization.

9. What statistics are available?
LoadingRack provides input and output flow, train fill ratio, product loading, train schedules, wagon availability, and wagon turnover statistics.

10. Can LoadingRack be used for long-term refinery simulations?
Yes. Direct Flow and Post-Schedule Operation can simplify loading operations or extend the model beyond the detailed train schedule for long-term refinery logistics analysis.