Canada's proposed high-speed rail line could cost up to $113 billion — 25% more than the government's current estimate — according to a new warning from the Parliamentary Budget Officer.

The PBO figure puts a substantially higher price on the project than the estimate officials have used so far, tightening the fiscal scrutiny around what would be one of the largest transport infrastructure commitments in the country's history.

What does the 25% gap mean?

A 25% overrun on a project of this scale translates into tens of billions of dollars in additional spending. The PBO's $113 billion ceiling exceeds the working estimate by roughly a quarter, meaning every funding scenario built on the lower figure now understates the likely call on public money.

Parliamentary budget officers do not set policy, but their cost assessments carry weight when cabinets prepare multi-year spending plans. A PBO warning at this level typically forces departments to defend their assumptions — on construction costs, contingency margins and financing — before contracts are signed.

Costs versus claims

The warning is a projection, not a measured result. No construction-stage spending data exists yet against which to test either the government's estimate or the PBO's higher ceiling. The gap between the two figures reflects differing cost assumptions, and both will be revised as engineering design and procurement advance.

For a project of this magnitude, early cost estimates carry a track record of undershooting final outlays. The PBO's intervention signals that parliament's independent fiscal watchdog expects the risk to run upward, not downward.

What comes next

The $113 billion figure now sits in front of lawmakers as the reference point for the funding debate. Decisions on the project's scope, financing structure and procurement schedule will determine whether the final cost lands near the government's estimate or closer to the PBO's ceiling.