Supply Chain Action Points
Read this first — the conclusion, and the moves to make:
- Before you rely on a ramp this quarter, audit its current dwell on your own boxes rather than the AAR total; if dwell on a lane you use has moved from two days toward five, treat that lane as constrained and add three days of buffer to every inland commitment.
- Split your rail volume plan into US intermodal and Mexican cross-border, because they tell different stories: plan capacity for the Mexican growth as structural and treat the US strength as partly a pull-forward.
- Re-check inland carrying cost at $28 per FEU per day and chassis fees at $25 to $40 a day, and put the surge cost in the budget line it actually hits, not in the rail line.
- Lock ramp appointments and chassis supply in writing for the next 90 days, since the surge that is invisible in the rate is plainly visible in the queue.
- Set a weekly dwell review against your own ramps and trigger a modal switch to truck or a re-routing decision if dwell exceeds four days for two straight weeks.
AAR data for the week ending 4 July showed total U.S. rail traffic of 582,121 carloads and intermodal units, up 8.7% year-on-year, with intermodal volumes up 12.9% - the seventh straight week of double-digit intermodal gains. Mexican rail intermodal rose 56%. Year-to-date U.S. traffic is up 3.4%, underlining a broad freight recovery.
The Analysis
The AAR reported that for the week ending 4 July, total US rail traffic reached 582,121 carloads and intermodal units, up 8.7 percent year on year, with intermodal alone up 12.9 percent. That was the seventh straight week of double-digit intermodal gains, and Mexican rail intermodal was up 56 percent. Year to date, US traffic is up 3.4 percent.
Read those two numbers against each other and a story appears that the rail traffic surges headline flattens. Total is up 8.7. Intermodal is up 12.9. That gap is the whole point, because it says the growth is not spread across the rail book. It is concentrated in boxes, and boxes come off ships and out of Mexico.
If your import flow touches an inland ramp, this is the number that tells you what the next month looks like before your carrier does.
Start with what intermodal is a proxy for. Intermodal is containerised freight, and on the US network that is overwhelmingly import-driven: a box lands at a port, runs inland on a train, and the rail number is the shadow the import volume casts onto the interior. Intermodal and carload are roughly equal halves of the book, so a total of 8.7 percent with intermodal at 12.9 percent implies carload growing at roughly 4.5 percent. The strength is narrow as well as real, and it has been running at double digits for seven weeks, which is long enough that it is no longer a spike. Add a 56 percent jump in Mexican intermodal and you have the second signal: cross-border manufacturing, the near-shoring story, showing up as rail volume rather than headlines.
Why now is partly a pull-forward and partly structural, and telling them apart is the job. Container imports into US ports have been running strong, and some of that is shippers pulling orders forward ahead of tariff timing, which is the unstable part, and some of that is the network genuinely re-routing to Mexico, which is the stable part. The rail number cannot separate the two, so you have to. A ten-week intermodal run that coincides with a frontloading window looks identical to a ten-week run that reflects a real shift, right up until the frontloading stops. The Mexican figure is the clue. A 56 percent jump is not a pull-forward. It is a corridor being built.
From the corridor this is a capacity story wearing a volume costume. Rail intermodal capacity is not elastic the way people assume. The trains exist, but the network behind them does not scale at the touch of a button: inland terminals, chassis pools, drayage fleets and ramp slots are all sized to a planning number, and when intermodal runs 12.9 percent above last year for seven weeks, the pinch moves. It moves out of the train and into the ramp. I have watched an inland terminal go from two-day to five-day dwell on nothing more exotic than a few extra trains a week, and the chassis that were waiting for boxes suddenly had boxes waiting for chassis. The surge you read in the AAR number is the front end of a dwell problem at the back end.
Who this lands on. The importer moving containers inland on a rail contract is the beneficiary and also the exposed one: they get reliable ramp-to-door service right up until the ramp fills, and then their transit turns into a dwell time they did not budget. The drayage and trucking operator at the inland ramp is squeezed first and hardest, because their capacity is fixed and their work is now queued. The bulk shipper in coal, grain or chemicals is the quiet one: their own volumes grow more slowly, but they share the network with the boxes, so they inherit congestion they did not cause and cannot price. The cross-border shipper into Mexico is the structural winner, because 56 percent growth is a corridor maturing rather than a swing. The trader who reads the headline and assumes everything on the railroad is booming has the wrong model. The book is not uniform: one half is modest and one half is hot.
Timing, and this is where the rail number is most useful. Rail intermodal is a lagging read on imports, not a leading one. A box discharged at a port typically reaches the rail ramp and then the AAR count within two to four weeks, so the number you are reading is what your ship already carried, not what is coming. That makes it a confirmation for the current month and a weak predictor for the next. What you can use it for is the second derivative: seven consecutive weeks of double-digit growth means the pace is sustained, and sustained pace is what overwhelms a fixed ramp. Watch your own ramp dwell, not the AAR total, for the early warning, because dwell moves before the carrier admits there is a problem.
The part the headline buries is that rail strength of this kind is a congestion signal before it is a demand signal, and the congestion does not show up where the volume does. A 12.9 percent intermodal run gets reported at the national level and felt at the ramp level, and the ramp is where chassis pools, drayage and appointment systems are sized for the average year. The second buried thing is the Mexican number. A 56 percent rise is not a surge you ride out, it is a network being rebuilt, and rebuilt networks re-tender their capacity in ways that leave the old routing short. If your inland plan assumes the ramps you used last year are the ramps you can use this year, and the growth is concentrated on a corridor you are not on, you will be competing for capacity that has already been committed elsewhere.
Run a number with the assumptions stated. Take an importer moving 40 FEU a week inland on a rail contract, ramp to door. Assume a base ramp dwell of two days and a landed carrying cost of $28 per FEU per day, and assume a sustained surge pushes dwell to five days, which my own corridor experience says is generous to the downside. That is three extra days on 40 boxes, or 120 box-days a week, at $28 a day, so about $3,360 a week, or roughly $175,000 a year if the surge holds. Add the drayage consequence: when chassis are short, the trucker bills a per-day chassis fee, commonly $25 to $40 a day, on the same boxes, which is another $3,000 to $4,800 a week under these assumptions. The rail line item did not change. The cost did.
What flips the read. If the intermodal strength is mostly frontloading, it is a loan against future volume, and the same ten-week run reverses in the second half when the pulled-forward orders stop. Then the ramps that were congested go quiet and the carriers who added capacity have to fill it. If it is the Mexican corridor maturing, it does not reverse, it compounds, and the congestion becomes a permanent cost line rather than a seasonal one. The tell is the ratio between the two series. As long as Mexican intermodal grows far faster than US intermodal, the structural part is real and worth planning capacity for. If the US number decelerates while Mexico holds, you are watching a pull-forward unwind, and you should not lock long capacity on the strength of it. Read the two series together, not the headline.
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