Truck vs Rail When Diesel Spikes: Efficiency, Flexibility, and Who Pays More (2026 Data)

On a gallon of diesel, a railroad moves a ton of freight about 3.5 times as far as a full truck does: nearly 500 miles by rail (AAR) against about 141 by truck (our calculation from ATRI's 2025 fleet average of 7.43 miles per gallon and a 19-ton payload). So when diesel rises by a dollar a gallon, a 2,000-mile truckload burns about $269 more fuel and the same load by rail with a short truck leg about $83 more.

Diesel did more than that in 2026. EIA's weekly US on-highway price was $3.897 a gallon in the week of Mar 2, 2026 and $4.859 a week later. It reached $6.529 in the week of Sep 21, 2026, the highest weekly print in a series that starts in March 1994 (the previous high was $5.810 on Jun 20, 2022). The latest print, for the week of Nov 9, 2026, is $6.127.

Who pays more is a different question from who burns more. Fuel is one part of a freight bill, the two modes reprice fuel on different clocks, and rail takes longer. This article sets out the numbers for each, with the arithmetic shown. It is not a rate quote or shipping advice.

The Association of American Railroads (AAR) says on its facts and figures page that railroads move “one ton of freight nearly 500 miles per gallon of fuel, on average” and that “on average, railroads are three to four times more fuel-efficient than trucks.”

One railroad shows its working. CSX's fuel efficiency page divides the 200,386,099,000 revenue ton-miles in its 2025 R-1 report by the 374,417,322 gallons of diesel it burned and gets 535 revenue ton-miles per gallon. The same page puts a truck at 134 ton-miles per gallon, from 19 tons carried 500 miles on 71 gallons at 7 miles per gallon.

For semi truck MPG, the American Transportation Research Institute's 2026 update on the operational costs of trucking (July 2026) reports that truck-tractors averaged 7.43 miles per gallon in 2025. By operating weight, its Table 18 runs from 6.20 MPG for fleets above 80,000 lbs. to 7.56 MPG at 60,001 to 70,000 lbs.

OPA calculation: 19 tons x 7.43 MPG = 141 ton-miles per gallon for a truck. Against AAR's rounded 500, rail is 3.5 times as fuel-efficient; against CSX's 535, 3.8 times. Both sit inside AAR's “three to four times”.

Three limits apply. The truck figure assumes a full 19-ton payload on every mile, and ATRI reports that 16.5% of non-tank truck miles in 2025 were empty. The rail figures are averages over all freight, including coal and grain in heavy unit trains; neither AAR nor CSX publishes a figure for intermodal trains alone on those pages. And a rail move usually needs a truck at one or both ends.

ATRI's Table 8 puts trucking's average marginal cost in 2025 at $2.336 per mile, of which fuel was $0.482. That is 20.6% (OPA calculation: 0.482 / 2.336).

For 2026, DAT Freight & Analytics gives one comparison in its Nov 10, 2026 release: “For a tractor and van trailer traveling 500 miles a day at 6 miles per gallon, fuel cost about $521 a day in October, compared with $310 in February.” That is $1.04 a mile against $0.62 (OPA calculation: each figure / 500). DAT's example uses 6 MPG, lower than ATRI's fleet average.

Railroads report fuel as a line in their income statements. The table divides that line by total operating expenses for 2025 and for the third quarter of 2026.

Fuel went from 16.3% to 24.4% of Union Pacific's operating expenses and from 11.4% to 18.4% of CSX's. In 2025 all four were below trucking's 20.6%; in the third quarter of 2026 Union Pacific and BNSF were above it. The periods differ in length, so this compares a quarter at 2026 diesel prices with a year at 2025 prices.

The railroad program below and DAT's truck fuel figures both use the EIA series charted above. They read it at different times.

Truckload fuel surcharges are set in contracts, and we have not read one. DAT describes the two markets in its Nov 10, 2026 release: spot rates “are negotiated as ‘all-in’ pricing, with no fuel surcharge”, while contract rates include fuel surcharges. DAT's estimated average van fuel surcharge was 83 cents a mile in October 2026, which it says is about double the year-earlier amount. In the same month DAT put the average van spot rate at $3.05 a mile and the average van contract rate at $3.28. Those are national averages, not lane quotes.

Union Pacific publishes one of its tariff programs. Its carload rate-based standard program starts at 1.5% of the linehaul charge when the monthly average diesel price reaches $1.35 a gallon and adds 0.5% for every five cents above that. It is billed “beginning the second month following the month on which the DOE average price calculation was based.”

The lag is easiest to see in the spring. Diesel averaged $3.722 in February 2026 and the weekly print was $5.401 by Mar 30, 2026, a rise of $1.679. Fuel for a truck costs that difference divided by its MPG: $0.28 a mile more at DAT's 6 MPG, or $560 over 2,000 miles; $0.23 a mile at ATRI's 7.43 MPG, or $452 (OPA calculations). A surcharge keyed to the weekly price moves in the week the price does. Union Pacific's published rate for April 2026 was still 25.0%, set by February's $3.722. The 37.0% that reflected March's $4.921 applied from May.

The same lag runs the other way on the way down. The weekly price peaked on Sep 21, 2026. Union Pacific's rate rose from 42.5% in October to 50.5% in November and stays at 50.5% in December, because those months use the September and October averages ($6.291 and $6.252).

This is one public tariff program. Union Pacific says its carload program “does not affect Union Pacific's Intermodal surcharge program”, and we have not read an intermodal or contract surcharge schedule from any railroad. Nothing here says what an intermodal shipper was billed. Our article on Union Pacific's Q3 2026 STB filing compares what the railroads collected in surcharges with what they spent on fuel.

This example counts gallons, not invoices. The inputs: an assumed 2,000-mile haul by either mode (our assumption, not a measured lane); a 19-ton payload (the figure CSX uses in its truck example); truck fuel economy of 7.43 MPG (ATRI, 2025); rail at 500 ton-miles per gallon (AAR, rounded); and 50 truck miles in total to and from the rail terminals (our assumption).

On these inputs the truck burns about 269 gallons and the intermodal move about 83. The fuel difference was about $682 a load at 2025's average price and about $1,142 at the Nov 9, 2026 price. The 2026 rise in diesel widened it by about $460 a load.

What would change the answer: a lighter load or a rail lane less efficient than the all-freight average narrows the gap; so do longer truck legs at each end, or a rail route longer than the highway route. Empty truck miles widen it. The gap in gallons is not a gap in price. Freight rates, surcharge schedules and terminal charges decide what a shipper pays, and none of them is in this table.

To run the truck side with your own figures, use the trucking cost-per-mile calculator.

AAR's Rail Industry Overview for November 2026 (a monthly publication, read Nov 13, 2026) reports that US intermodal volume in October 2026 “rose 9.6% over last year and set an all-time monthly volume record”, and that railroads “averaged more than 298,000 intermodal units per week in October 2026, the highest weekly average ever for a month.”

AAR lists the causes together: “high diesel, insurance, and maintenance costs for truckers; fewer available truck drivers; and solid rail service performance.” It also says growth spanning most traffic categories is “not a one-off and not just market share gains from trucks”. The page gives no figure for how much of the intermodal gain came from trucks.

On the truck side, DAT's Truckload Volume Index for dry vans was down 2% year over year in October 2026, and DAT's Dean Croke said equipment posts “are running about 22% to 26% below last year depending on the equipment type.”

We found no sourced diesel price at which freight tips from truck to rail, and this article does not propose one.

Rail's fuel advantage comes with a schedule. Carrier-published transit figures are scarce, so this section is short. Union Pacific's Aug 7, 2025 release announced a domestic intermodal service from Southern California's Inland Empire to Chicago “with three days' transit”, starting Sep 3, 2025 at “five days a week”, and described it as “up to 20% faster” than current industry offerings between those points. That is terminal to terminal on one lane.

We did not find a carrier-published truck transit time for the same lane and do not state one. A truck leaves when it is loaded and delivers to the door; an intermodal load waits for a train departure and needs a truck at each end. How many days that adds depends on the lane, and the section below treats it as an input.

The claim to test: the 2026 diesel rise opened a wider gap between truck and intermodal fuel cost, and a shipper who can wait can capture it. Stated as arithmetic, a slower mode is cheaper on these two items when the fuel difference exceeds the cost of holding the cargo for the extra days.

The inventory carrying cost formula: carrying cost = cargo value x annual carrying rate x extra days / 365. Break-even cargo value = fuel difference x 365 / (annual carrying rate x extra days).

Inputs. The fuel difference is $1,142 a load, from the table above at the Nov 9, 2026 price of $6.127 (at 2025's $3.660 it was $682). The annual carrying rate and the extra days in transit are yours to supply: we have no sourced value for either, so the tables show 10%, 20% and 30% a year and one to three extra days as assumptions.

Read against the fuel difference of $1,142: at an assumed 20% a year, three extra days cost $164 on a $100,000 load and $1,644 on a $1,000,000 load. The break-even at 20% and three days is about $695,000 of cargo; at 2025's diesel price the same break-even was about $415,000 (OPA estimate: $682 x 365 / (0.20 x 3)). The rise in diesel moved the line; it did not create it.

Assumptions, and what would change the answer. The fuel difference carries every assumption of the example above. It is a difference in fuel burned, priced at retail, not a difference in freight rates: a shipper sees it only to the extent rates and surcharges pass it through, and DAT reports van spot linehaul rates, which exclude fuel, up 55 cents a mile year over year in October 2026. Carrying cost here ignores the safety stock a less predictable transit time may require, and any cost of a late delivery. The window comes from fuel intensity, not from the two-month surcharge lag: the lag shifts when a rail surcharge is billed, not how many gallons a train burns.

This is arithmetic on public inputs. It is not a forecast of diesel, rates or volumes, and not a recommendation to route any shipment.

What is intermodal shipping?

AAR's intermodal page defines it this way: “Rail intermodal combines trains for the long haul with trucks or ships at one or both ends of the trip. The goods stay in the same container as it moves between modes”.

Is rail cheaper than truck?

On fuel, yes on the figures above: about 83 gallons against about 269 for the example load. On price, the sources here do not say. DAT publishes national truck rate averages, and we have not read a published intermodal rate. Fuel was about a fifth of trucking's cost per mile in 2025 (ATRI), so the rest of the bill matters more.

How is a fuel surcharge calculated?

By a schedule that converts a diesel index into a charge. Union Pacific's public carload program adds 0.5% of the linehaul charge for every five cents the monthly EIA average is above $1.35, starting at 1.5%. We have not read a truck schedule; the fuel surcharge page tracks the weekly DOE diesel index.

Why did rail surcharges keep rising after diesel peaked?

Because Union Pacific's published program uses the average price of two months earlier. The weekly price peaked at $6.529 on Sep 21, 2026. Union Pacific's rate for October 2026 (42.5%) used August's $5.462; its November and December rates (50.5%) use September's $6.291 and October's $6.252.

The EIA weekly price behind every calculation here is on the live diesel price page, and in the API as DIESEL_RETAIL_USD. For this article the weekly values were taken from EIA's own table.