Logistics Optimization
Why is Multimodal Scheduling Hard?
Multimodal planning can involve a number of different transport modes within a single journey of a container. With each additional leg and each new mode more complexity is added.
Imagine a shipment that is to be transported from Factory A to Customer B, both of which are a long distance from a port. This may require five legs, as shown below:
Leg 1
Factory A
to
Intermediate Terminal IT1
via
Truck
Leg 2
Intermediate Terminal IT1
to
Port of Loading P1
via
Rail/Barge/Feeder
Leg 3
Port of Loading P1
to
Port of Discharge P2
via
Ship
Leg 4
Port of Discharge P2
to
Intermediate Terminal IT2
via
Rail/Barge/Feeder
Leg 5
Intermediate Terminal IT2
to
Customer B
via
Truck
1: Truck from Factory A to First Terminal IT1
2: Rail/Barge/Feeder IT1 to Port of Loading P1
3: Ship from P1 to Port of Discharge P2
4: Intermodal from P2 to Second Terminal IT2
5: Truck from IT2 to Final Destination B
The majority of the journey will be made by ship as this is usually the most economic. Hinterland movements can be made via rail, barge or feeder vessel and connect the port to intermediate terminals. Getting to and from the intermediate terminals may require truck movements.
Schematic of Multimodal Routes from A to B via Intermediate Terminals (IT) and Ports (P). In reality many more terminals and ports could be considered.
For such a movement there are many choices:
- Leg 1 - ~10 reasonable choices for the inland terminal
- Leg 2 - ~5 reasonable choices of deep sea port for loading the container
- Leg 3 - ~5 possible ports for discharging the container
- Leg 4 - ~10 possible inland terminals close to the final destination
This gives 2500 possible route combinations to move from Factory A to Customer B.
However, for each leg there are multiple options for carriers and services. Assuming there are 10 options for each leg there would be a total of 250,000,000 possible options to choose from for a single shipment.
The problem can be even more complex when taking into account multi-leg ship movements and combinations of hinterland modes.
When all the possible options for the shipment have been found there is still the issue of how to determine the “best” choice. Should cost be the sole factor or does the emissions produced also have an impact? Is there a strict deadline for the shipment?
Often a combination of factors such as cost, risk, emissions and arrival time come in to play when finding the best fit route for a shipment.