Rail traction: Unit economics
Why wiring a railway pays only where trains run often
What this tab covers What it costs to move a unit of energy this way: capital and operating costs, tariffs, utilisation and how it compares with the alternatives.Electric trains are cheaper to run than diesel but need expensive fixed wires; electrification pays where traffic is dense. Diesel-electric operators cut fuel mainly through engine upgrades and, newly, batteries.
Key costs
| Measure | Value | Note |
|---|---|---|
| UK electrification cost, simpler projects | 0.75-1.0 million GBP per single-track km (2019)14 | troubled recent projects GBP 2-2.5 million |
| Running cost, electric against diesel trains | over 35% cheaper%14 | RIA citing a 2009 UK Department for Transport estimate |
| Battery locomotive fuel saving (pilot) | about 11%% of train fuel use11 | 2.4 MWh FLXdrive in a BNSF consist, California, 3 months in 2021; about 6,200 gallons saved; second generation above 6 MWh could save up to 30% |
| Engine upgrade fuel saving | up to 7%% additional fuel saving10 | Wabtec EVO Advantage upgrade, 2025 |
| Global new rolling stock market | 64.6 billion EUR (2024)6 | top ten makers about 70% |
| Saving from a steady UK electrification programme | about 30% (range 16-37%)% of infrastructure cost15 | RIA estimate, 2026 |
| US on-highway diesel price | 5.19 USD per gallon (2026 average, EIA October 2026 outlook)16 | retail including taxes; used in the worked example |
Where the money goes
| Item | Share or amount |
|---|---|
| Route clearance in UK electrification (raising bridges, lowering track) | 30-40% of the cost of some schemes14 |
| Rolling stock in Alstom sales | about 52% of EUR 19.2 billion (calculated: 10,045 of 19,171 million)8 |
| Energy losses per 100 units at the wheel, modern electric train | transformer 7.5, converter 4.7, motor and gearbox 12.2, auxiliaries 9.9, parked 8.41 |
Worked example: the FLXdrive pilot saved about 6,200 gallons of diesel in three months. At EIA's 2026 average US on-highway diesel price of USD 5.19 per gallon that is about USD 32,000 (calculated), or roughly USD 129,000 a year if repeated (calculated); railways buy fuel in bulk without road taxes, so their saving per gallon is lower. Battery locomotive prices are not published in the checked sources, so payback cannot be computed; savings are largest on hilly routes where braking recharges the battery. BHP is commissioning two 7 MWh FLXdrive units on its Pilbara iron ore lines in Western Australia.
Sources
- Traction systems for high-power applications (brochure, Rev B) (company data) ABB, 2018
- Worldwide Rolling Stock Manufacturers 2025 (reading sample) SCI Verkehr, 2025
- Alstom's fiscal year 2025/26 results Alstom, 2026
- Advantage Wabtec: relentless innovation drives Evolution Series engines into the future Wabtec, 2025
- Wabtec: battery-electric locomotive reduces fuel use by 11% FreightWaves, 2021
- Electrification Cost Challenge Railway Industry Association (RIA), 2019
- Electrification Cost Challenge 2.0 Railway Industry Association (RIA), 2026
- Short-Term Energy Outlook, October 2026, Table 2 (US energy prices) US Energy Information Administration, 2026