NanoEFX for rail
NanoEFX is a passive, water-based air-filter treatment for combustion engines with a treatable intake filter or intake medium. It can be applied to diesel rail engines where such a filter or medium is present. We have not yet run a rail trial, however, so we do not assign a fuel-saving or emissions figure to locomotives, multiple units or maintenance machines.
| Treatment | Passive, water-based air-filter coating — not a fuel additive or ECU remap |
|---|---|
| Applies to | Diesel locomotives · Diesel multiple units · Rail-maintenance machines |
| Fuels | Diesel · Biodiesel (no field validation) · HVO renewable diesel (no field validation) |
| Application | Existing filter treated (20–45 min) or pre-treated filter fitted |
| Reapplication | By run-hours & engine size (locomotives are measured in operating hours) |
| Engine changes | None — no modification, remap or retrofit |
| Regulatory context | EU Stage V engine-emission standards (incl. railway engines) |
A coating on the air filter — not a fuel additive or a remap
NanoEFX is sprayed onto the engine's air filter — the existing one, or a replacement filter treated in advance — where it dries into a thin, breathable nano-coating. As the engine draws air through that treated surface, the coating is designed to condition the intake air before combustion, with the aim of supporting a cleaner, more complete burn — what we have measured is set out below. For a rail fleet, that means the same treatment can be applied to every engine that breathes through a treatable filter — whether it lowers fuel use on a given engine is what a pilot measures.
What it is
- A passive nanostructured intake-air treatment
- Applied to the engine’s air filter
- Water-based — dries to a thin, breathable coating
- Works before combustion, at the intake-air stage
What it isn't
- A fuel additive or oil additive
- An ECU remap or tuning
- A mechanical retrofit or powered device
- Anything that changes how you operate
Three pressures every rail operator already feels
These are the forces that make intake-air efficiency worth acting on — independent of any single engine or duty cycle.
Diesel fuel is a core cost off the wires
On non-electrified lines, diesel fuel is a dominant operating cost. If a pilot measures a gain that holds over a representative period, even a modest one could add up over long run-hours; whether it carries over to other locomotives is checked separately.
Emissions scrutiny on diesel traction
Rail engines fall under non-road emission standards such as EU Stage V, and operators face pressure to cut diesel emissions where electrification is not present. Combustion theory would expect a more complete burn to produce less CO and unburned hydrocarbons; we hold one accredited measurement on one vehicle and none on soot.
Lower-emission freight expectations
Freight customers increasingly ask for lower-emission transport and report their supply-chain emissions. Burning less fuel directly lowers the emissions attributed to a service.
Want the numbers for your own fleet? The Fleet Fuel & Carbon ROI calculator models fuel-cost savings from your own figures and shows how carbon is priced for your country and fuel — added only where it is paid on top through emissions trading.
Regulatory sources: EU Stage V — Regulation (EU) 2016/1628 (non-road engines) · Other regions (USA, Japan, China, and more) →
No trial data from this sector
Why this sector matters — independent figures
Electrification of the EU rail network rose from 39.9% of lines in 1990 to 57.6% in 2024. The remaining two-fifths of the network is worked by diesel traction — which is the part of rail this page is about.
Source: Eurostat — characteristics of the railway network in Europe. Published by the organisation named; retrieved 15 August 2026. These are sector figures, not our measurements — ours are below.
We have no rail data. No locomotive, railcar or shunter has been measured in any trial we hold.
The nearest evidence we hold
Nothing in our records is a close analogue. Rail traction runs long, steady, high-load duty, which is closer to marine main-engine operation than to road transport — and we hold no marine fuel figure we stand behind, because the one trial series that measured fuel did not follow the reapplication protocol we now recommend. The marine finding that does hold is not a fuel figure at all but a third-party engine inspection after 1,875 operating hours.
What a trial here would have to look like
Diesel traction is well instrumented and duty is repeatable, so a rail trial could be unusually clean: the same units on the same rosters, treated and untreated, over a season, with fuel drawn from the depot and tonnage logged.
Marine engine compatibility
Third-party inspectionThe nearest long-duty engine evidence we hold — an inspection result, not a fuel figure.
Read the trial →All trial results, including the weak and mixed ones → · every individual measurement we hold
How a trial is run and what each method can show: measurement methodology. What we measured at the exhaust: emissions. Everything in one place: the evidence section.
From a mainline locomotive to a maintenance machine
A rail operation is rarely one engine. NanoEFX can be applied to diesel rail engines that breathe through a treatable air filter, and it works at the intake air, whatever the fuel burned.
Equipment types
Fuels
For the fuels marked above we have no documented field validation, so we make no performance claim for them.
No workshop, no retrofit, no new hardware
Your own team either fits a pre-treated filter, or treats the existing filter, lets it dry for at least 20 minutes and refits it.
What this could mean for a rail fleet
NanoEFX doesn't add energy or oxygen and doesn't modify your engine — it is designed to help the engine waste less of the energy already in the fuel. NOx response is engine- and control-system dependent.
Common questions from operators
Can NanoEFX be used on our diesel locomotives?
Does NanoEFX change the engine or its control systems?
How often does NanoEFX need reapplying on a locomotive?
Does NanoEFX help where lines are not electrified?
Does NanoEFX affect the DPF, SCR, EGR or AdBlue system?
Don't take the claim — measure it
The most honest evidence is your own baseline. In a NanoEFX pilot you run a controlled trial on your own engines, measured against your own fuel data — and you only pay if it proves savings.