The Client (Tier 1 Iron Ore Miner) needed to assess whether the introduction of a significant amount of new rolling stock assets (both locomotives and wagons) would be able to be maintained with their current maintenance workshop infrastructure and layout. The quantity of the Client’s fleet was planned for an approximate 75 % increase over the next 5 years and with a staged commissioning strategy.

Considerations

• Over 10 different types of service/maintenance activities – each of different durations, intervals and requiring different equipment and parts to complete
• Typical unscheduled losses or unplanned failures of equipment
• Maintenance of the facility and other system outages
• Current maintenance backlog

With the workshop already under pressure to keep up with the current fleet’s maintenance demand, the simulation was to determine the right amount of upgrades or expansions to make that would minimise capital expenditure while still meeting the servicing needs of the new fleet.

The Solution & Method

The GreenNet OptiSim team worked with the Client to map out the process (see sample in Appendix A) and replicate it within the application. Once the model was built, validation was conducted to ensure the simulation represented the reality of current operations as closely as possible. Appendix B shows the main list of parameters (can be flexed) and constraints for the model.

Optimisations and scenarios were run with different parameter sensitivities to assess what configurations would be optimal to service the new fleet while keeping the backlog to a minimum and ensuring any unplanned events could be reasonably recovered from.

Key metrics tracked in the simulation model were as follows:

• # OC (ore car) through the workshop/year
• # Locos through the workshop/year
• Loco Bay utilisation
• OC bay utilisation & OC Portal Lathe utilisation
• OC Backlog
• Loco Backlog & Time in Backlog
• Loco road utilisation
• Key workshop asset utilisation
• Wheelset farm float & Wheelset Queue

Key inputs were provided to the client to allow them to run further scenarios in the future as new information became available; these included:

• Various service times and steps
• Service intervals
• Fleet makeup
• The ability to toggle on and off key assets and additions to the workshop
• Wheelset floats and wheelset farm capacity

Allowing the Client to vary these values allowed them to consider further options after the completion of the primary study. This provided a tool to ensure that key goals could be met if the initial parameters of the model changed at a later date.

The Results & Conclusions

1. The current facility would not support the maintenance requirements of the new facility.
2. A new maintenance road would need to be constructed with an additional two wagon/ ore car maintenance bays for ‘fast work’ services to ensure throughput and backlog can be managed
3. The wheel lathe is well utilised until major servicing of new assets is required in the future when it becomes the bottleneck. This can be mitigated somewhat by improved dynamic scheduling by operations teams.
4. Bringing on a night shift is not required if suggested upgrades are made.

In summary, the simulation project provided key insights to the Client that informed the efficient use of capital and demonstrated potential risks the Client should prepare for.

Appendix A

Appendix B