High-Speed Rail: the material
we need is under our feet
Building a railway takes millions of tonnes of stone. Where it comes from has real consequences for cost, emissions, and your community.
ALTO is deciding between two corridors. Building a high-speed railway requires millions of tonnes of broken and crushed rock. Whether that material is dug up along the route itself — or trucked in from somewhere else — has real consequences for cost, CO₂ emissions, and the roads in your community.
Along some potential routes, material excavated during construction can be used to build the railway itself, saving taxpayers hundreds of millions of dollars, cutting truck traffic by over a million journeys, and dramatically reducing the project’s environmental footprint.
This page explains how — and why it matters to you.
What is ALTO deciding — and what does rock have to do with it?
ALTO is planning a new high-speed railway between Ottawa and Toronto through Eastern Ontario. Before any track is laid, the project team must choose a route. Two different corridors (from which one route will be selected) are on the table: the northern corridor includes Highway 7 and a southern corridor that would cut through more populated areas and ecologically sensitive land.
Building a railway requires enormous quantities of rock, gravel, and stone — collectively called aggregate. These materials are needed for everything from the roadbed the track sits on, to the ballast (crushed stone) that holds the rails in place, to the concrete used in bridges and tunnels. On a project this size, we are talking about tens of millions of tonnes.
Where that material comes from matters enormously. If it has to be dug up somewhere else and trucked to the site, the costs — financial, environmental, and social — are huge. If the route itself sits on top of suitable rock, those costs largely disappear. The Northern Route sits on top of some of the best construction rock in Ontario. The Southern Route does not.
What is under the Highway 7 corridor?
Eastern Ontario sits at the edge of the Canadian Shield — some of the oldest and most durable rock on Earth. But this region of the Shield is not a monolith. The Northern Route passes through three geological zones, each offering a different type of useful material.
Ottawa to Lanark — Limestone country
The eastern section crosses the St. Lawrence Lowlands, where the bedrock is Ordovician limestone — ancient seafloor laid down 450 million years ago. This makes excellent crushed stone for road bases and concrete. The area also has extensive deposits of glacial till, ideal for filling embankments along the railway.
Lanark to Sharbot Lake — Where the Shield begins
As you move west, the ancient Canadian Shield starts to push through to the surface. Here you find granite, gneiss, and marble alongside the limestone — a transition zone that has been quarried for over a century. The area has an established quarrying industry and community acceptance of this kind of work.
Sharbot Lake to Kaladar — Premium granite
The western section crosses full Canadian Shield — billion-year-old Precambrian rock that includes sediments and harder felsic rock. Both rock types are valuable. The latter is exactly the material used for rail ballast — the crushed stone that holds railway tracks in position. It is so strong and resistant to weathering that once placed, it can last a century with minimal maintenance. There is more than enough here to supply the entire project.
The Total Picture
Taken together, the three zones along the Northern Route contain an estimated 32 to 47 million tonnes of usable construction material directly in the path of the proposed railway. To put that in perspective, the entire project needs roughly that amount to build. In other words, the route digs up most of what it needs as it goes.
What does this mean for taxpayers, communities, and the environment?
When a construction project can source its materials from the dig itself rather than importing them from elsewhere, the benefits flow in several directions at once.
What happens if the material has to be brought in from somewhere else?
This is the reality facing the Southern Route. That corridor does not have the same geological advantages. Its bedrock is unsuitable for rail ballast and much of what is excavated cannot be reused. That means millions of tonnes of material would need to be trucked in from quarries elsewhere in Ontario — and millions of tonnes of waste would need to be trucked out to landfill.
What a Million Truck Journeys Looks Like
Independent analysis suggests the Southern Route would require roughly one million truck journeys for aggregate alone. Those trucks have to travel on existing roads — including county roads and municipal streets through towns and hamlets. The damage to road surfaces alone runs to tens of millions of dollars, and compensation from large infrastructure projects routinely falls short of covering the actual cost to communities.
The UK’s HS2 project — the most comparable recent railway construction anywhere — generated 3 million truck movements in Buckinghamshire alone. Local councils received far less in compensation than the roads cost to repair. Ontario’s spring road restrictions would make this problem significantly worse here.
Road damage and who pays for it
Construction trucks are heavy. Rural roads in Eastern Ontario are not built for sustained heavy traffic. When roads are damaged, it is typically the municipality — and therefore local taxpayers — who bear the cost, even when a formal compensation mechanism exists. The gap between what projects pay and what damage actually costs has been documented repeatedly in comparable projects.
Community disruption
A million truck journeys mean noise, dust, road closures, and slow traffic for years. For communities along affected roads, this is not an abstract number — it is a daily lived experience for the duration of construction. Highway 7, as an existing heavy-traffic arterial road, is designed and built to handle this. Side roads, county roads, and village streets are not.
The Northern Route avoids almost all of this
Because the Northern Route generates most of its own material on-site, the need for imported aggregate is dramatically reduced. Construction equipment stays largely within the railway corridor itself. And where material does need to move in bulk, the CP Rail line running alongside the corridor can carry it by train instead.
Northern Route vs Southern Route: the material sourcing comparison
The table below summarises the key differences between the two routes from a materials and community impact perspective.
| Factor | Northern Route (Hwy 7) | Southern Route |
|---|---|---|
| Rock quality for ballast | Excellent — billion-year-old Shield granite | Poor — unsuitable for rail ballast |
| Material available on-route | 32–47 million tonnes — meets project needs | Insufficient — large imports required |
| Truck journeys for aggregate | Dramatically reduced through on-site sourcing | Approximately 1 million+ journeys required |
| Financial impact of materials | $250–400M net saving to the project | Significant additional cost |
| Construction waste to landfill | Near zero — 95%+ reuse target achievable | Large volumes of unsuitable spoil |
| Impact on local roads | Low — Hwy 7 handles heavy traffic by design | High — rural and municipal roads under sustained pressure |
| Population density | Low — established corridor with quarrying acceptance | Higher — more communities affected by construction |
| Carbon emissions | 25,000+ tonnes CO₂ avoided | Significantly higher emissions from haulage |
Source: Independent geological analysis · Comparison with UK HS2 project data
What can we learn from the UK’s HS2 railway?
HS2 is Britain’s high-speed rail project — the most comparable recent large railway construction project anywhere in the world. It has been both a source of valuable lessons and, in some areas, a cautionary tale.
What HS2 proved: reusing excavated material works
On Phase 1 of HS2, the project team committed to reusing excavated material rather than sending it to landfill. They achieved a 95% landfill diversion rate. They also shifted bulk material onto the railway network itself rather than roads, replacing 181,500 truck journeys with trains and saving 19,000 tonnes of CO₂ in the process. These are proven figures, not projections. The Northern Route has the geology to match or exceed all of them.
What HS2 got wrong: road damage and community impact
Where HS2 had to bring material in by road, communities paid a heavy price. In Buckinghamshire, roads suffered severe damage from construction traffic and compensation was inadequate. Some residents described the experience as devastating. This is the scenario that local materials sourcing on the Northern Route largely avoids.
The key difference with Eastern Ontario
HS2 faced a far more difficult challenge than ALTO does on the Northern Route. British geology does not provide the premium hard rock that Eastern Ontario’s Canadian Shield offers. And HS2 was built through heavily populated areas where road-based construction was often unavoidable.
The Highway 7 corridor offers better rock, better logistics, and far less community disruption. We have the opportunity to do this better than HS2 did — if we choose the right route.
The Northern Route gives something back to Highway 7 communities
The surplus aggregate generated by railway excavation — granite and limestone that the project does not need — can be used to repair and upgrade Highway 7 after construction is complete. Rather than the road being left in worse condition, the community ends up with a better road. This is a direct, tangible benefit to the people who live and work along the corridor.
The Circular Logic
The railway digs up rock. The rock builds the railway. The leftover rock improves the road that was used during construction. Communities along Highway 7 end up with better infrastructure, not worse. This kind of circular benefit is only possible because of the Northern Route’s exceptional geology.
What does this mean for the environment?
Far fewer truck emissions
Over a million fewer truck journeys means over 25,000 fewer tonnes of CO₂ entering the atmosphere. It also means less diesel particulate pollution in the communities those trucks would otherwise pass through.
No new quarries opened for this project
Bringing in aggregate from elsewhere means either expanding existing quarries or opening new ones — disturbing land, blasting rock, and creating noise and dust. On the Northern Route, the quarrying happens within the railway footprint itself. No new greenfield sites are disturbed. Agricultural land is preserved. Wildlife habitats outside the corridor are protected.
Near-zero waste
A 95% or higher material reuse target means that almost nothing from excavation goes to landfill. Avoiding it is better for communities, better for the environment, and better for the project budget.
Aligns with Canada’s climate commitments
Canada has committed to net-zero carbon emissions by 2050. The Northern Route’s material sourcing strategy is the kind of real-world emission reduction that Canada’s climate targets require.