The UK government is about to commit a multi-billion pound act of economic self-harm in the name of "fiscal responsibility."
Whispers from Whitehall suggest ministers are ready to order HS2 to run at lower speeds—dropping from 225mph to roughly 125mph—to shave a fraction off the immediate capital expenditure. It sounds like a sensible compromise. It sounds like a way to save the taxpayer’s bacon. Expanding on this idea, you can find more in: Why the Green Party Victory in Manchester is a Disaster for Keir Starmer.
It is actually a delusional retreat that turns a high-speed rail project into a very expensive, very redundant commuter line.
By slowing down the trains, you don't just lose time. You lose the entire business case for the project. When you gut the speed, you gut the capacity and the competitive edge against short-haul flights and car travel. If we wanted 125mph trains, we should have just upgraded the West Coast Main Line in 2005. To do it now, at these costs, is like buying a Ferrari and then paying a mechanic extra to install a speed limiter that caps it at 40mph. Experts at NPR have also weighed in on this matter.
The Fatal Flaw of the Slower-is-Cheaper Myth
The "lazy consensus" among pundits is that air resistance and power consumption are the primary cost drivers of HS2. They argue that $P \propto v^3$ (power is proportional to the cube of velocity), so cutting speed should save a fortune.
Mathematically, that is true for an engine. Economically, for a national infrastructure project, it is a lie.
The vast majority of HS2’s costs are sunk into land acquisition, tunneling, planning litigation, and the physical laying of track. Once you have dug the Chiltern tunnels and poured the concrete for the viaducts, the "savings" from running a train 50mph slower are negligible compared to the loss in revenue.
High-speed rail isn't a luxury for people in a rush. It is a capacity solution.
When trains run at varying speeds on the same line, you create massive gaps in the timetable. This is the "mismatch" problem. A dedicated high-speed line works because every train moves at the same blistering pace, allowing you to stack them like planes in a landing pattern—one every few minutes.
If you slow HS2 down to match the speed of existing regional services, you lose the ability to run 18 trains per hour. You might drop to 8 or 10. You are essentially building a four-lane motorway and then telling everyone they have to drive at the speed of the slowest tractor.
Why "People Also Ask" Is Asking the Wrong Questions
If you look at public forums or "People Also Ask" sections, you see the same flawed inquiries:
- Can't we just use existing tracks?
- Is 20 minutes saved really worth £100 billion?
These questions miss the point entirely. HS2 was never about getting a businessman from Birmingham to London 20 minutes faster. It was about getting the long-distance expresses off the old tracks so that local stopping services, freight trains, and regional commuters could actually have a reliable timetable.
The West Coast Main Line is the busiest mixed-use railway in Europe. It’s a clogged artery. By building a new "super-pipe" for the fast stuff, you clear the old pipe for everything else.
If you make the new "super-pipe" slow, the fast stuff stays on the old tracks longer, or the new line becomes so unattractive that the shift in passenger behavior never happens. You end up with two mediocre railways instead of one elite one and one functional regional one.
The Invisible Cost of "Value Engineering"
I have seen departments blow through budgets on "value engineering" exercises that end up costing more in the long run. In the private sector, if a project's ROI (Return on Investment) depends on a specific performance metric—in this case, speed—you do not compromise that metric to save 5% on the upfront cost.
If the government mandates slower trains, they will have to:
- Redesign the rolling stock specifications, potentially triggering massive contract penalties with manufacturers like Alstom and Hitachi.
- Re-evaluate the signaling systems, which were designed for high-frequency, high-speed intervals.
- Accept a lower ticket price premium, because nobody pays a premium for a "medium-speed" rail.
The Treasury is looking at the balance sheet for 2027. They should be looking at the economic productivity of the UK in 2050. Britain is already an outlier in Western Europe for its crumbling, Victorian-era infrastructure. We are the only nation that views "high speed" as a debatable luxury rather than a basic requirement for a modern economy.
The Engineering Reality: You Can't Undo the Geometry
There is a technical arrogance in thinking you can just "dial back" a project of this scale. The tracks are already being laid with specific gradients and curvatures designed for high centrifugal forces.
If you run trains slower on tracks banked for high speeds, you actually increase wear and tear on the "low" rail. This is basic physics. The maintenance costs for running slow trains on high-speed geometry can actually be higher in specific sections because the weight isn't distributed as intended by the designers.
Let’s look at the actual energy equation for a moment:
$$E_k = \frac{1}{2}mv^2$$
While kinetic energy increases with the square of velocity, the "savings" in energy from slowing down are a rounding error compared to the opportunity cost of the seats you cannot sell because your turnaround times are now 30% longer. A train that takes 90 minutes to do a journey instead of 60 minutes is a train that can perform fewer total trips per day. That is fewer tickets sold per asset.
It is a productivity killer disguised as a cost-cutting measure.
Stop Fixing the Wrong Problem
The problem with HS2 isn't the speed. The problem is the British obsession with gold-plating every station and allowing every local council to demand a three-mile tunnel to protect a view of a shed.
If the government actually wanted to save billions, they would:
- Standardize station designs. Stop making every stop an architectural masterpiece. We need functional sheds with platforms, not glass cathedrals.
- Reform the planning laws. We spend more on lawyers and environmental consultants for HS2 than some countries spend on the actual steel and concrete.
- Commit to the full route. The "stop-start" nature of UK infrastructure adds a "uncertainty tax" to every contract. Contractors hike their prices because they don't know if the project will exist in six months.
Cutting the speed is the "easy" political win because it sounds like common sense to a voter who has never managed a CAPEX budget larger than a kitchen renovation. In reality, it is the ultimate "penny wise, pound foolish" maneuver.
The Harsh Truth of Modern Rail
High-speed rail is a binary. Either you have it, or you don't.
France's TGV and Japan's Shinkansen work because they are uncompromising. They represent a different tier of travel that effectively shrinks the geography of the nation. When you shrink geography, you move the talent pool. You allow someone to live in a more affordable northern city while contributing to a high-value hub.
If you make the train slower, you keep the geography large. You keep the North isolated. You keep the "London bubble" intact because the friction of travel remains too high for daily or even thrice-weekly interaction.
We are currently on track to spend £100 billion to arrive at the same place we started: a rail network that is "just okay" and perpetually behind the curve of our global competitors.
If the government proceeds with this order, they aren't saving HS2. They are embalming it.
Stop trying to "save" the budget by ruining the product. If you aren't going to build a high-speed railway, don't build it at all. Cancel the whole thing and spend the money on fiber optics and local bus routes. But do not build a monument to mediocrity and call it progress.
Either build the 225mph spine the country needs, or admit that Britain is no longer a country capable of doing big things. There is no middle ground, and there are no savings to be found in the slow lane.
Get it done, or get out of the way.
