Maintenance
Cost categories
Planned, part-level work carried out at a fixed interval. Every maintenance record belongs to a specific part — never to the locomotive as a whole.
Maintenance Cost = Quantity × Price, once per interval
Includes
- +Parts consumed at each service (quantity × unit price)
- +Scheduled inspections, overhauls and rebuilds
- +Both time-based (months) and usage-based (hours / km) intervals
Excludes
- −Labour — calculated separately as a percentage
- −Unplanned failure repairs
Labour
Cost categories
The workshop cost of performing maintenance. It is never entered by hand — it is derived from the parts spend on every occurrence.
Labour Cost = Sum(Part Prices) × 18% (percentage editable in the Library)
Includes
- +Technician time to fit the parts
- +Applied at every maintenance event
Excludes
- −Parts cost itself
- −Overheads billed separately
Consumables
Cost categories
Fluids and short-life items replaced on a fixed cadence rather than on condition. Expensed, not capitalised.
Includes
- +Oils, coolants, greases, refrigerant
- +Filters and gaskets
- +Anything with a sub-year replacement interval
Excludes
- −Rotables and unit-exchange parts
- −Anything carrying a core credit
Failures
Cost categories
Unplanned breakdowns — the expected cost of parts failing before their scheduled replacement, weighted by how likely each failure is.
Failure Cost = Failure Probability × Repair Cost
Includes
- +Replacement part plus the labour to fit it
- +A cascade premium where one failure damages downstream parts
- +Weighted by failure probability, not counted as a certainty
Excludes
- −Failures still inside the warranty window — those sit under Warranty
Downtime
Cost categories
Revenue lost while the locomotive is out of service. Measured from the moment the unit stops earning to the moment it returns to traffic.
Downtime Cost = Days Out of Service × Revenue per Active Day
Includes
- +Time to repair (MTTR) valued at the daily revenue rate
- +Both planned service windows and unplanned outages
- +Warranty outages counted at half rate — the unit is still unavailable even when the repair is free
Excludes
- −The repair cost itself — that is Maintenance or Failures
Warranty
Warranty & risk
The period during which the manufacturer, not the operator, pays for a failure. Cover has two limits and ends at whichever is reached first.
Covered = (Years elapsed ≤ Warranty Years) AND (Km run ≤ Warranty Km)
Includes
- +Warranty in years — for parts that age
- +Warranty in kilometres — for parts that wear with use
Failure Probability
Warranty & risk
How likely a given part is to fail within its warranty window, expressed as a percentage. Trended against hours in service rather than held as a fixed number.
Includes
- +Derived from criticality and replacement cadence
- +Rises with accumulated wear
- +Editable per part in the Library
Company Buffer (Warranty Reserve)
Warranty & risk
The money the organization should set aside per part to cover warranty claims it expects to receive.
Company Buffer = Part Cost × Failure Probability
Includes
- +Held per part, then rolled up across the BOM
- +Recalculates whenever price or failure probability changes
Customer TCO
TCO views
Everything the operator actually pays across the planning horizon.
Customer TCO = Total Cost − Warranty-Covered Cost
Includes
- +Maintenance parts and derived labour
- +Consumables
- +Out-of-warranty failures
- +Downtime
Excludes
- −Anything the warranty covers
- −The manufacturer's warranty reserve
Organization TCO
TCO views
What the manufacturer carries — the mirror image of the customer's bill.
Organization TCO = Warranty-Covered Cost + Company Buffer
Includes
- +Warranty replacement cost
- +Service forecasting
- +Company warranty reserve across all parts
Maintenance Interval
Rates & intervals
How often a part needs attention, expressed in the unit that actually governs it. Where several limits apply, whichever is reached first triggers the work.
Includes
- +Running hours — engine internals
- +Kilometres — running gear and brakes
- +Months — calendar-driven inspections
Extended Cost
Rates & intervals
The cost of a whole part line rather than a single unit.
Extended Cost = Unit Price × Quantity per Component
Includes
- +Used for BOM roll-ups and depreciation
Depreciation
Rates & intervals
How a capitalised part loses book value over its useful life. Each part depreciates on its own schedule (IAS 16 component approach).
Includes
- +Straight-line for steady-wear parts
- +Units-of-production where charge scales with utilisation
Excludes
- −Consumables — expensed as incurred, never capitalised