The “Shield Is Too Expensive”
Claim Doesn’t Hold Up
A cost comparison — roughly $50M/km for the southern route versus $80M/km for a northern one — has been publicly circulated and cited in a Senate committee submission. These numbers are actively influencing a multi-billion-dollar, irreversible decision about where high-speed rail will go.
No geotechnical evidence has been published to support either number. Two independent geological experts have now examined the record — and found that the claim that Shield geology makes a northern route prohibitively expensive is not supported by the geology.
A 5 km-wide band of easily excavated rock runs directly along the Highway 7 corridor through the Canadian Shield. It is not hard granite — it is meta-sedimentary rock. Engineers in the 1880s and again in the 1930s independently built major infrastructure along it, leaving measurable proof in the landscape of what the geology naturally allows.
This analysis does not argue for the northern route. It argues that no route should be ruled out — or ruled in — based on cost claims that have never been subjected to independent geological scrutiny.
Three things we’ve been told — and what the geological record actually shows
The following claims have been circulated publicly in the context of the ALTO route debate, including in a submission to the Senate Standing Committee on Transport. Each has shaped public and political opinion. Each is examined against the geological record below.
The Canadian Shield is hard granite requiring extensive blasting and tunnelling. A northern corridor would therefore be prohibitively expensive.
The southern route avoids the Shield and therefore has significantly lower construction costs — potentially saving billions of dollars.
The southern corridor does not avoid difficult geology. It must cross the Frontenac Terrane — some of the hardest granite in the region — before encountering extensive unstable glacial deposits. It also runs 30 km longer. 1
Cost estimates of approximately $50M/km (southern) vs. $80M/km (northern) are credible and reliable enough to shape route selection.
These figures have been publicly cited but no geotechnical basis for them has ever been published. The assumptions behind them must be disclosed before they can be trusted. 4
The Shield is not all the same rock — and that difference is everything
When people picture the Canadian Shield, they often imagine a single vast slab of hard granite. That image is wrong — and it’s the source of the misconception that has distorted this entire cost debate. The portion of the Shield relevant to ALTO, called the Grenville Shield, is a mosaic of very different rock types formed about one billion years ago. The two types that matter for construction cost are as different as concrete and clay.
🪨 Meta-Sedimentary Rock
Dominant along Highway 7
Former sandstones and limestones, transformed over millions of years. Despite their age, they have a flat, layered structure that’s relatively straightforward to work with. Modern equipment can cut through them with minimal or no blasting. They create predictable, manageable conditions for building a rail line.
This is the rock type that runs along the Highway 7 corridor. The fact that 1930s engineers built a flat, straight highway exactly here is itself geological evidence of these conditions. 2
🔥 Hard Igneous Rock (Granite)
Dominant in the Frontenac Terrane
Granite and granite gneiss. Unconfined compressive strength can exceed 250 MPa — among the hardest materials encountered in any construction project. 1 Excavation requires extensive blasting, often tunnelling, and creates irregular terrain that forces expensive alignment curves.
This is the rock type the southern corridor must cross through the Frontenac Terrane. The claim that the southern route “avoids the Shield” obscures the fact that it goes through the Shield’s most challenging geology.
Why does this matter for cost?
Construction cost is driven largely by how hard the rock is, how much needs to be removed, how stable the ground is for foundations, and how far materials must be transported. The public debate has assumed the northern corridor is the hard, expensive option. The geological record suggests the opposite may be true — and that no one has published the evidence needed to know for certain.
Two generations of engineers already showed this corridor is buildable
The meta-sedimentary band along Highway 7 isn’t a theory. It has been tested in practice twice — by engineers working generations apart with very different technology. Both times, independently, they identified the same corridor and built along it. The results are still measurable today.
The Former CP Rail Line (1880s) 6
The former CP Rail line — now the Trans Canada Trail — was built in the 1880s using Victorian-era equipment: no powered excavation, just horse-drawn scrapers and hand labour. These engineers crossed the Canadian Shield and achieved a gradient that is, by modern measurement, comfortably within the operational specifications for high-speed rail.
Highway 7 (1930s) 7
Engineers in the 1930s, with no knowledge of the 1880s rail line, independently chose to build Highway 7 along the same meta-sedimentary corridor. The result is visible to anyone who drives it today: flat and straight for 15 km stretches north and west of Kaladar, with minimal grade change. This was not engineering overcoming difficult terrain — it was engineering that recognised and followed the geology.
Hyett & Peterson Elevation Profiling (2026) 1
Hyett and Peterson’s detailed modern survey of the corridor confirms what the historical infrastructure demonstrates. The 70 km from west of Sharbot Lake to Madoc is remarkably flat buildable terrain — measured consistently across three independently profiled segments.
Engineers in the 1880s and again in the 1930s already identified the right corridor through the Shield. The geology has not changed. The obligation to account for it has not either.
The southern corridor has its own geological challenges — and no one is talking about them
This analysis does not argue the southern corridor is unworkable. It argues that a deeply one-sided public debate — where the northern corridor’s challenges are repeatedly cited while the southern corridor’s are ignored — cannot produce a credible cost comparison.
The Frontenac Terrane: The hardest rock in the region
The southern corridor must cross the Frontenac Terrane — hard felsic granite and granite gneiss with unconfined compressive strength potentially exceeding 250 MPa. 1 This is the hardest rock type in the Grenville Shield. Construction here requires extensive blasting, possibly tunnelling, tighter alignment curves around terrain obstacles, and crossings of major lakes. The “avoids the Shield” framing is geologically inaccurate — the route crosses the Shield’s most challenging geology.
Glacial Till: Unstable, expensive foundations south of the Shield
South of the Shield, the southern corridor encounters extensive Champlain sediments — glacial till characterised by high variability, frost susceptibility, perched water tables, moisture sensitivity, and slope instability. Building high-speed rail on this requires deep piling and long-term management of settlement and frost heave. Estimated spoil removal: 4–5 million tonnes — more than double the less than 2 million tonnes estimated for the Highway 7 alignment. 1
Aggregate Logistics: A million truck journeys to bring the ballast in
High-speed rail requires 2–3 million tonnes of premium crushed granite ballast. 9 For the southern corridor, this must be imported from distant quarries — an estimated 1 million truck journeys for aggregate delivery plus 500,000 for waste spoil removal. That generates over 25,000 tonnes of additional CO₂ and imposes real costs on municipal road networks. 1 The Highway 7 corridor, by contrast, would encounter the felsic granite needed for ballast as a natural by-product of its own (limited) igneous zone crossings.
Distance: 30 km longer before any other factor is considered
The southern corridor is approximately 269 km versus an estimated 239 km for the Highway 7 alignment — 12.5% longer. Every additional kilometre of track, at any cost-per-km figure, adds directly to the total bill.
Side-by-Side Geological Comparison 1
This comparison is drawn from Hyett and Peterson’s independent assessment. It is not a recommendation for either corridor — it is a statement of what the geological record shows, set against what has been publicly claimed.
| Factor | Highway 7 Corridor | Southern Corridor (as proposed) |
|---|---|---|
| Total Distance | 239 km | 269 km (+12.5%) |
| Hard Igneous Rock | Less than 6 km crossing | Extensive Frontenac granite |
| Dominant Terrain | Flat meta-sedimentary | Rugged granite, then glacial till |
| Glacial Till Volume | Less than 2 million tonnes | 4–5 million tonnes |
| Aggregate Sourcing | Largely local, on-site felsic | Imported (~1 million truck journeys) |
| Excavation Method | Largely without blasting | Extensive blasting / tunnelling |
| Foundation Type | Standard embankment | Deep piling in glacial till |
| Published Cost Basis | None publicly available | Claimed lower — no geotechnical evidence published |
Source: Hyett & Peterson (2026) 1 · This comparison is provided for context, not as a route recommendation.
Six things that must be released before any route decision is made
A decision that will commit billions of dollars of public funds and permanently reshape eastern Ontario is currently being driven by cost figures with no published geotechnical basis. The following information is required for any credible assessment — and none of it has been made public.
“The public and decision-makers are being asked to engage with a process in which the technical basis for the key cost differential claim remains undisclosed.”
Five demands — grounded in standard engineering practice
These demands are addressed to ALTO HSR and to federal and provincial decision-makers. They reflect standard practice for infrastructure planning at this scale — not exceptional requests, but the minimum required for a credible process.
Release the geotechnical assumptions behind all published cost estimates
Rock types, excavation methods, foundation specifications, and material volumes assumed in the circulated cost figures must be disclosed so they can be independently verified. Cost claims that cannot be checked cannot be trusted.
Commission and publish a geotechnical investigation of the Highway 7 corridor
The meta-sedimentary band has been validated by two independent infrastructure projects and mapped by the Ontario Geological Survey. A formal HSR-specific geotechnical survey should be completed and published before route selection proceeds.
Apply equal geological scrutiny to the southern corridor
The Frontenac Terrane crossings, glacial till foundation requirements, and aggregate import logistics of the southern corridor must receive the same level of public geotechnical analysis currently being demanded of the northern options.
Do not foreclose any route on the basis of unverified claims
No corridor — including alignments not currently under formal consideration — should be advanced or eliminated based on cost claims that have never been subjected to independent geological review.
Establish an independent geological review mechanism
A formal process must be created through which qualified geological experts can review cost assumptions before a route decision is locked in by planning expenditure. This is standard practice for infrastructure decisions of this scale and irreversibility.
This is not an argument for the northern route
Sources
In-text citations use bracketed numerals. Where sources are unpublished technical reports prepared for public distribution, this is noted.