A story about some new trains got me thinking

Sometimes an apparently unrelated news story sends you back to an old question.

On 11 September 2026, the Government announced an investment of around £1 billion in 29 new battery-electric trains for TransPennine Express. The trains will operate principally from overhead electricity where it is available, but batteries will allow them to continue over sections of railway which are not electrified.

On the face of it, this has nothing whatsoever to do with the Lower Thames Crossing.

But it prompted an interesting discussion about optioneering.

Why use batteries rather than electrify every mile of railway? What does the whole-life cost comparison look like? How much would completing the electrification cost? How frequently would batteries need replacing? At what point does partial electrification plus battery operation become more economical than installing overhead wires throughout?

Those are exactly the questions that a good options appraisal ought to answer.

And that brought me back to something LTCA has been asking, in various forms, for the better part of ten years:

Did we ever ask the right question about the Lower Thames Crossing?

The difference between a road problem and a transport problem

The Lower Thames Crossing is intended to relieve congestion at Dartford, improve resilience and provide better strategic connectivity, including connectivity between Britain’s ports and the rest of the country.

The Department for Transport’s latest assessment, published in 2026, continues to emphasise connectivity to major ports and improved resilience and reliability for freight users.

Yet the project that emerged is overwhelmingly a road solution.

That distinction matters.

If the question is:

“Where should we provide additional road capacity across the Lower Thames?”

then naturally the answer is going to be a road.

But suppose the original question had instead been:

“How can Britain most efficiently provide additional capacity and resilience for moving people and freight between the Channel and Thames ports, the Midlands, the North and Scotland?”

Suddenly the range of possible answers becomes much wider.

Road is one.

Rail is another.

A combination of road and rail is another.

Intermodal freight terminals, additional rail capacity, selective infrastructure upgrades and targeted improvements to the existing Dartford Crossing could potentially form another.

I am not suggesting that any of those alternatives would necessarily have beaten the Lower Thames Crossing.

The important point is that we don’t know.

Meanwhile, something interesting was happening in France

In March 2016, at around the time Britain was progressing its plans for the Lower Thames Crossing, a service called VIIA Britanica began operating between Le Boulou, close to the Spanish border, and Calais.

It remains in operation today.

The concept is remarkably simple.

Instead of a tractor unit and driver hauling a semi-trailer approximately 1,200 kilometres across France, the trailer is loaded onto a train.

The train carries it from Le Boulou to Calais in around 22 hours.

At Calais the trailer is transferred to a ferry and travels unaccompanied to Britain, where another tractor can collect it.

VIIA says its service therefore avoids approximately 1,200 kilometres of road travel. It can accommodate a variety of equipment including refrigerated trailers, hazardous-goods trailers and P400 semi-trailers.

The driver does not travel with the load. Neither does the original tractor unit.

That raises a question we remember discussing years ago.

Why does the train stop at Calais?

What if it didn’t?

What if a semi-trailer originating in Spain could be placed on a train near the French-Spanish border and remain on rail through France, through the Channel Tunnel and onwards through Britain?

Perhaps to the Midlands.

Perhaps Manchester.

Perhaps ultimately Scotland.

Local road haulage would still be required at either end. But the long-distance trunk movement could potentially be made by rail.

It isn’t as simple as connecting two railway lines together. There are substantial engineering and operational problems.

But the idea is certainly not fantasy.

In fact, Britain considered it before

One particularly interesting piece of evidence dates all the way back to 2000.

Evidence presented to Parliament by the Rail Freight Group discussed a railway loading gauge known as W18, large enough to accommodate four-metre-high road trailers carried on railway wagons.

It reported that the then Strategic Rail Authority was studying W18 gauge:

from the Channel Tunnel to Glasgow.

Why?

Because much of the corresponding traffic was travelling in lorry semi-trailers on the parallel motorway network.

In other words, more than a quarter of a century ago Britain was already considering the basic concept we are discussing here:

Channel Tunnel → London → Midlands → North → Glasgow

with road semi-trailers travelling by rail.

It didn’t happen.

But the historical significance is important.

This is not an idea invented by opponents of the Lower Thames Crossing in 2026. It is a transport concept which has been considered before.

What would it actually take?

We are not attempting a feasibility study in this article.

That would require considerably more work.

But it is worth understanding some of the principal obstacles, because they demonstrate that the question is an engineering and economic one rather than simply “trains can’t do that”.

Loading gauge

One of the first problems is loading gauge.

This is not the distance between the railway tracks. It describes the maximum height and width of a train and its load.

Britain’s historic railway infrastructure generally has a smaller loading gauge than continental European railways.

That matters when you want to put a full-size road trailer onto a railway wagon.

Network Rail has progressively sought to increase parts of Britain’s strategic freight network to larger W10 and W12 gauges, principally to accommodate modern containers and a wider range of wagon/load combinations.

Its 2017 Freight Network Study identified W12 clearance between the Channel Tunnel and Wembley as a highest-priority freight-gauge scheme. The same study identified W12 improvements on the West Coast Main Line and elsewhere.

But full-size P400 road trailers present a more demanding challenge.

Hence the historic interest in W18.

A feasibility study would therefore need to identify every restrictive bridge, tunnel, platform and other structure along a potential route.

Some might require major reconstruction.

Others might require comparatively modest intervention.

Track can sometimes be lowered beneath a bridge. Bridges can sometimes be raised or replaced. Platforms can be modified. Specialist low-floor wagons can reduce the required overall height.

The correct question is therefore not:

“Will a P400 trailer fit on Britain’s railway?”

It is:

“What prevents a P400 trailer from travelling along a particular strategic route, and what would it cost to remove those constraints?”

That is measurable.

Capacity and train paths

Making a train physically fit does not mean there is space in the timetable to run it.

Freight trains compete for railway capacity with passenger services.

This is particularly important around London and on heavily used main lines such as the West Coast Main Line.

Freight trains may also accelerate more slowly than passenger trains and travel at different speeds. That can consume disproportionately large amounts of capacity on a busy mixed-traffic railway.

Possible solutions could include freight loops, signalling improvements, junction remodelling, additional tracks and carefully planned freight paths.

Again, none of this is free.

But neither is constructing 14 miles of new motorway and Britain’s longest road tunnel.

The comparison I would like to see is the cost of overcoming one set of constraints against the cost of overcoming the other.

Train length

A seemingly mundane issue can dramatically affect the economics: how long can the freight train be?

A train carrying perhaps 30 trailers has very different economics from one carrying 15.

Network Rail’s freight strategy has previously identified 775 metres as the desired minimum baseline for intermodal freight trains across the core network.

Long trains require suitably long terminals, sidings and passing loops.

So another perfectly reasonable engineering question would be:

Which locations prevent 775-metre international freight trains operating between the Channel Tunnel and major British logistics centres, and what would it cost to remove those restrictions?

Getting through or around London

This could prove one of the more difficult constraints.

A freight train emerging from the Channel Tunnel has to reach the principal routes heading towards the Midlands and North through one of the busiest railway environments in Britain.

The optimum solution might not follow the most obvious geographical route.

A proper study would need to examine existing freight routes around London, available capacity, loading gauge, junction constraints and connections to the West Coast, Midland and East Coast corridors.

And something has happened in 2026 which makes this particularly interesting.

Regular Channel Tunnel freight is coming back

In February this year, the Government announced a deal under which Network Rail and its property company Platform4 will take long-term control of Barking Eurohub in east London.

Around £15 million of private investment is envisaged to develop the site as an international logistics hub.

The objective is explicitly to facilitate the return of regular intermodal freight trains through the Channel Tunnel.

Government says this could provide British businesses with direct rail freight links to France, Germany, Italy and Spain.

It even mentions the possibility of Scottish whisky travelling by train to European customers.

So the concept of freight travelling between continental Europe and distant parts of Britain by rail is no longer merely something found in a 25-year-old parliamentary document.

It is current Government policy.

But there is one sentence in the Government’s announcement which particularly caught my attention.

It says increased international rail freight would help reduce road congestion, particularly:

at the Dartford Crossing and on the M20/M2 corridors.

Think about that for a moment.

In 2026, while progressing an enormous new road crossing whose strategic justification includes freight and connectivity to ports, the Government is simultaneously promoting Channel Tunnel rail freight partly because moving freight from road to rail could reduce congestion at Dartford.

That deserves rather more examination.

Freight terminals and the first/last mile

Rail freight does not eliminate road haulage.

Nor does it need to.

Imagine a trailer beginning its journey near Barcelona.

A Spanish tractor takes it to an intermodal terminal.

The trailer travels by rail through France, the Channel Tunnel and Britain.

It terminates at a logistics terminal in the Midlands.

A British tractor takes it the final 30 miles to its destination.

The road journey hasn’t disappeared.

The long-distance road journey has.

That distinction is important.

And because VIIA’s model carries the trailer unaccompanied, the tractor and driver don’t spend the entire journey travelling with it.

That potentially saves not only fuel but tractor utilisation and driver hours.

Suitable British terminals would obviously be required, positioned near major distribution centres and with sufficient capacity to transfer trailers efficiently between road and rail.

The Midlands might therefore be just as important as Scotland.

A European trailer terminating in the Midlands may already have avoided several hundred miles of British motorway travel.

Not every lorry using Dartford could go by rail

This is where we need to be careful.

Nobody should interpret this article as suggesting that every HGV using the Dartford Crossing could simply be placed on a train.

It couldn’t.

A lorry travelling between Gravesend and Thurrock is obviously not a sensible candidate for rail.

A trailer travelling from Spain through Dover and onwards to Manchester might be.

The critical evidence would therefore be an origin-destination analysis of freight using Dartford.

How many HGV movements are local?

How many originate at the Channel ports?

How many are travelling to the Midlands, North or Scotland?

What commodities are being carried?

How many movements are time-sensitive?

How many loads could realistically transfer to rail?

And what would operators actually be prepared to pay?

Only after answering those questions could anyone sensibly estimate the potential modal shift.

Don’t just count lorries at Dartford

There is another important consideration.

Suppose one train removes 30 HGVs from the Dartford Crossing.

Against the enormous daily traffic flow at Dartford, 30 vehicles doesn’t sound particularly significant.

But suppose each of those 30 lorries would otherwise have travelled another 250 miles.

The train has potentially removed 7,500 HGV-miles from Britain’s roads.

Repeat that with several trains every day in both directions and the relevant measure becomes much larger than the number of vehicles removed from one river crossing.

That could mean reduced congestion elsewhere, reduced road wear, fewer emissions, lower accident exposure and potentially lower demand for future highway capacity.

The correct metric therefore isn’t necessarily simply:

How many vehicles can we remove from Dartford?

It could also be:

How many long-distance HGV-kilometres can we remove from Britain’s strategic road network?

What could £8.9 billion buy?

And inevitably we come back to money.

The latest Department for Transport assessment puts the Lower Thames Crossing’s estimated cost at around the £9 billion scale and continues to classify the assessed funding options as Low value for money.

The project nevertheless has what the Department describes as a strong strategic case.

This article isn’t another attempt to recalculate its BCR. LTCA has examined the economic case elsewhere, including in our LTC Options Comparison – Merits Only analysis.

We want to ask a different question.

We know broadly what expenditure on the scale of £9 billion buys us if directed towards the Lower Thames Crossing:

a new strategic highway and another road crossing of the Thames.

What we don’t know is what investment on anything approaching that scale could have achieved if directed instead towards Britain’s strategic freight railway.

How much of the Channel Tunnel-to-Midlands route could have been gauge-cleared?

Could a route have been cleared for P400 trailers?

Which London bottlenecks could have been addressed?

How much additional freight capacity could have been created?

How many 775-metre freight trains could have been accommodated?

Which terminals could have been constructed or expanded?

Could the investment have provided a genuine strategic freight spine from continental Europe through the Channel Tunnel to the Midlands, North and Scotland?

And ultimately:

how many HGV journeys and HGV-miles would it have removed from the M20, M25, Dartford Crossing, M1 and M6?

We don’t currently have the answers.

But £9 billion is enough money that I think the questions deserved to be asked.

Rail may not have won

This point is important enough to state explicitly.

A proper study might conclude that the railway alternative was prohibitively expensive.

Britain’s restrictive loading gauge could make the necessary structural work uneconomic.

London railway capacity might prove an enormous constraint.

The economics of transporting trailers could fail at the distances and volumes involved.

Operators might prefer conventional road haulage.

The number of Dartford HGV movements realistically transferable to rail might simply be too small.

It is entirely possible that a rigorous multimodal appraisal would have concluded:

Build the Lower Thames Crossing.

If so, that would have been powerful evidence in its favour.

But equally, it might have identified a package of rail, intermodal and more modest highway improvements offering better value.

Or perhaps the optimum solution would have involved both modes, with rail absorbing a greater share of long-distance freight while targeted road investment addressed the journeys that could not transfer.

That is what optioneering is supposed to discover.

You don’t begin by deciding which answer you want.

You define the problem.

You identify credible alternatives.

You develop them sufficiently to make a meaningful comparison.

Then you decide.

Ten years later, perhaps the question needs asking again

The irony is that this article began with a news story about passenger trains in northern England.

Those new battery-electric trains prompted a discussion about why one engineering solution had been selected over another and what the cost-benefit analysis behind that decision might look like.

That conversation eventually brought me back to the Lower Thames Crossing.

And then to something I remember asking approximately a decade ago:

Why does VIIA Britanica stop at Calais?

Ten years later, VIIA is still carrying road trailers 1,200 kilometres across France by train.

Britain is now actively trying to restore regular Channel Tunnel rail freight.

Government is talking about direct rail freight connections with France, Germany, Italy and Spain.

It is talking about Scottish exports travelling to Europe by train.

And, remarkably, the Department for Transport itself now says that increasing Channel Tunnel rail freight could help reduce congestion at the Dartford Crossing.

Meanwhile, the Lower Thames Crossing continues towards construction at a cost approaching £9 billion, despite currently sitting within the Government’s Low value-for-money category.

Perhaps rail would never have been an alternative to the LTC.

Perhaps it could only ever have complemented it.

Perhaps a serious investigation would have shown that the engineering constraints were simply too expensive to overcome.

We don’t know.

And that is really the point.

Ten years after Britain committed itself to solving the Lower Thames problem principally by providing more road capacity, we still cannot point to an equivalent developed proposition showing what a strategic programme of rail-freight investment might have achieved.

So perhaps we were asking the wrong question.

Instead of:

“Where should we build another Lower Thames road crossing?”

perhaps the question should always have been:

“What is the most efficient way of moving people and goods between Britain’s ports and the rest of the country?”

Only after answering that question should we have decided whether the answer needed to be a road.

A question for another day

This article isn’t the feasibility study.

But perhaps it identifies one worth doing.

What would it actually take, in 2026, to create a high-capacity international freight corridor capable of taking continental trailers from the Channel Tunnel to the Midlands, North and potentially Scotland?

Where are the physical pinch points?

What gauge could realistically be achieved?

What would the infrastructure cost?

How much capacity would be available?

What proportion of long-distance road freight could realistically transfer?

And how would the resulting benefits compare with major strategic highway investment?

More than 25 years ago, Britain’s rail industry was already discussing a Channel Tunnel-to-Glasgow railway capable of carrying road trailers.

Ten years ago, as the Lower Thames Crossing emerged, VIIA Britanica demonstrated the concept on the other side of the Channel.

Today, Government wants international rail freight back — and tells us that one of the benefits will be less congestion at Dartford.

Maybe it is time somebody finished the optioneering.