The UK Government has committed to achieving a net-zero economy by 2050. Two years ago, it set a target for rail freight growth of at least 75 per cent. Those ambitions are simple to state, but far more complex to realise. What do the prospects of net-zero and 75 per cent growth really mean? RailFreight.com UK Editor Simon Walton puts at least three-quarters of his net effort into finding the answers.
Putting “75 per cent growth” on the tracks, while reforming the economy down to net-zero by 2050, is something even the National Audit Office admits remains a “colossal challenge”. Even in base logistics terms, increasing the roughly 600 daily freight trains by something like 450 extra workings exercises the assumptions that demand, paths and locomotive power can all be found. A simplistic observation, but that’s what “colossal challenge” means. All this, and there are still hundreds of megatons of carbon being emitted annually, even in industrially diminished Great Britain.
Wide scope for rail, but big issues too
Rail freight offers an appealing and visible opportunity to demonstrate intentions. Shifting goods from road to rail could deliver primary, secondary and tertiary carbon reductions. One freight train can realistically replace dozens of lorries, with far fewer emissions than by road. It’s a win for the industry, the environment and, possibly most importantly, the politicians.
However, even if rail freight throughput were to double, triple, or more, it would still remain a small fraction of the total UK logistics market. Today, rail accounts for only eight to ten per cent of domestic freight tonne‑kilometres. By comparison, road carries more than eighty per cent. Modal shift to rail does help, but even a modest effort to decarbonise heavy goods vehicles could rival or exceed the climate benefit of expanding rail freight alone.
Add to that, a “net-zero-ready” rail freight fleet is also still a long way off. In 2025, the bulk of UK freight locomotives will remain diesel-powered – something it has in common with much of the rest of the world. A rough power-type breakdown of the current UK fleet is approximately 75 per cent diesel, 15 per cent bi-mode (with some tri-mode), and 10 per cent pure electric.
The fleet, however, is not frozen in time. A slow renewal is underway. The introduction of modern bi-mode, dual-mode and tri-mode locomotives offers a path toward lower-carbon freight, especially as electrification of mainlines gradually expands (Midland Main Line excepted, of course) and battery or low-carbon fuels come into play.
More freight operators are investing in future-proof traction. GB Railfreight (GBRf), for instance, has ordered 30 Stadler-built Class 99 electro-diesels. The first four are here already. The units are built to run on overhead electric power – or on diesel – and, critically, they’re HVO ready. The specialist traction provider, Rail Operations Group (ROG), is still experimenting with their tri-mode Class 93. They have plans for up to thirty units, capable of electric, diesel or battery operation, providing adaptability on mixed or partially electrified routes.
There are still pure-electric freight locomotives (older re-engineered passenger units) but their numbers remain modest, reflecting decades in which diesel traction was the norm. Electric freight locomotives now constitute around nine per cent of the total locomotive fleet.
Obstacles to decarbonisation ambitions
Adoption of alternative fuels, such as HVO (hydrotreated vegetable oil), has been successfully trialled and even put into revenue-earning service. However, for the next generation of traction, which will be active come that 2050 deadline, operators definitely favour multi-mode traction flexibility – out of necessity. They have to avoid being locked out of non-electrified routes – while the UK Government continues to prevaricate over fully wiring up the network.
The challenges remain substantial. Full electrification is unlikely to reach every siding or port by 2050. Even if electrification increases, and even if multi-mode locos proliferate, the pace of change will likely remain gradual. The existing diesel fleet has many years of useful life ahead, and operators have limited incentive to retire well-functioning diesels while they remain cost-effective.
What net zero really means — and how rail freight fits in
Politicians are invited to take special note of this next point. When we talk about net-zero rail freight, we often fall into the trap of seeing the rail industry in abstract from its overall economic contribution. It might mean a fully decarbonised freight-loco fleet: electric, battery, or renewable-fuel traction throughout. On the other hand, it could mean that freight modal shift to rail reduces overall transport emissions. The holistic view is preferable, especially if rail works in concert with low-carbon HGVs, inland waterways, and better logistics planning.
The scale is the thing. Even if rail freight achieved 75 per cent growth by 2050 and converted its fleet to low- or zero-carbon traction, the proportion of goods moved by rail would still be modest compared with road freight. For that reason, achieving a net-zero logistics sector will require progress on multiple fronts — rail freight, decarbonised HGVs, inland waterway freight, modal integration and demand-side change.
Not quite ready — but poised for transformation
The technology exists. The next generation of diverse-power freight locomotives is on order, being built or already entering service. Rail freight operators are embracing them. Overhead electrification continues to expand, sporadically and unevenly across the country, and where sufficient power supply exists, freight can run on zero-carbon electricity (just don’t mention the northern section of the East Coast Main Line).
Today, the foundation of the network remains overwhelmingly diesel. For rail freight to deliver on that 2050 net-zero mandate, fleet turnover must continue steadily for two decades. Gradual removal of legacy diesel, widespread uptake of multi-mode and electric traction, and complementary infrastructure investment will all be needed. The greatest virtue of this current diesel dominance is that it gives us time. With 25 years before 2050, there is a runway for transformation. If operators, government and customers align, the UK could deliver a freight railway that is not just greener — but future-proof. It makes so much sense, it’s almost un-British in its readiness.