Fleet transition
Stay diesel, electrify in place, or resize the fleet and electrify — costed per corridor, not asserted.
For every corridor Urban Pathways ranks, the fleet question has two layers: which of three scenarios to run on that corridor — keep running diesel, electrify the existing fleet in place, or electrify with the vehicle size re-optimised — and, where corridors share a hub, whether to consolidate them into one branching trunk before electrifying at all. Each corridor scenario is costed on the same whole-of-life basis, so an authority facing a fleet transition can see what each path costs before committing to one. This is a screening result, not a procurement business case.
Three scenarios, one basis
Stay diesel keeps the corridor on its current or nearest diesel-bus fleet, priced against the same twenty-year horizon as the other two paths, so it is a like-for-like baseline rather than a status-quo assumption.
Electrify in place swaps the existing fleet for electric vehicles of the same size and count, and returns the fleet size, vehicles in service, frequency, headway and capacity that follow, along with annual vehicle-kilometres, annual driver hours, and well-to-wheel emissions.
Electrify and resize goes further and re-optimises vehicle size for the corridor before electrifying, on the view that a fleet built around diesel constraints is not necessarily the right fleet to electrify.
All three carry battery-replacement scheduling, the point at which a zero-emission mandate would force a switch regardless of cost, carbon priced at seventy dollars a tonne, and pavement wear. The unit that makes them comparable is whole-of-life cost per boarding.
The cost basis
Every scenario runs on a twenty-year analysis horizon. Present value is reported at both seven and ten per cent, the ATAP sensitivity range, alongside the undiscounted cash figure, so a reviewer can see the result under more than one Treasury assumption rather than one chosen in advance. Capital and operating costs are split rather than blended, and charging capital is priced as the existing per-route-kilometre infrastructure cost that applies to any electrified corridor, not a location-specific build.
Hub-level architecture, costed separately
The three scenarios above hold each corridor’s route architecture fixed: electrify in place and electrify and resize both keep the corridor running as its own point-to-point route and only re-optimise vehicle size within that shape. A city can electrify its existing routes one for one on that basis, or it can ask whether the routes themselves should be consolidated first. Urban Pathways evaluates both.
Where corridors converge on a shared hub, Urban Pathways costs combining them into one branching trunk against running them independently, and attributes the resulting saving between the powertrain switch and the architecture change separately, so a reviewer can see which decision carries the value. Thirteen hubs are evaluated on the Sydney run, the largest with eighteen branches.
The hub-level attribution below is now approved for external use. Each figure is whole-of-life cost over a twenty-year horizon, undiscounted cash, with carbon priced at seventy dollars a tonne, from the Sydney screening run as at 28 August 2026.
- Macquarie Park and Marsfield, 18 branches — powertrain switch $35.8 million; architecture consolidation $178.0 million.
- North Parramatta, 8 branches — architecture consolidation $97.4 million.
- Wentworth Point and Sydney Olympic Park, 6 branches — architecture consolidation $50.9 million.
Limits on the hub-level view. The capital saving from consolidation comes from running fewer, larger vehicles under trunk sizing; it is not a reduction in charger count, a term the model does not carry. Pooling and sizing assume a coincident morning peak across the corridors sharing a hub — a conservative simplification rather than a measured staggering — and modelling staggered peaks would be expected to reduce the reported saving. Hub membership counts a corridor at both of its endpoints, so hub-level figures are not additive across hubs.
What this does not answer
Urban Pathways shows the depot and charging cost implications of a fleet decision. It does not tell a city where to put chargers: the per-vehicle depot-charger capital model behind that question is switched off, unpopulated, and not approved for use outside the product team.
Nor does it publish a citywide or portfolio total across every corridor’s electrification path. That comparison exists inside the product, carries a provisional flag, and is withheld from this site until WaterRoads approves it for external use. What is published here is the per-corridor method, not a market-wide result.
This is still a screening step. It narrows the fleet question to a comparison worth taking into a business case; it does not replace that business case, and it does not forecast patronage.
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