100 mm and 10 Tonnes: The Limits Your Quote Never Mentions
Your quotation gives you a rate, a transit time and a corridor. It does not mention the two limits a station master applies before your cargo is allowed onto a wagon, and either of them can hold a shipment that is otherwise in perfect order.
Neither limit is about how much your cargo weighs. Both are about where that weight sits.
Two words that sound alike and are not
Chinese rail practice uses two terms that English tends to flatten into “imbalance”, and they are measured differently, limited differently and corrected differently.
Eccentric load (偏载) is sideways drift: the cargo’s centre of gravity, projected onto the wagon floor, falls to one side of the wagon’s longitudinal centreline by more than the permitted amount.
Longitudinal imbalance (偏重) is drift along the wagon: the centre of gravity moves toward one end, so one bogie carries more of the load than the other.
Behind both sits a single idea. Put the centre of gravity over the point where the wagon’s two centrelines cross — rail operators call it the wagon centre. If you have ever stood on a floating raft, you already know why: that is the one spot where nothing tips. The rulebook does not pretend cargo ever lands exactly there. It sets limits instead.
The 100 mm line
China’s rules for the loading and securing of freight — the 加规, in daily use — allow the lateral offset to run to 100 mm from the longitudinal centreline, and no further.
The interesting part is what happens past that line. You are not asked to pack more carefully. You are asked to counterweight: to load other goods on the opposite side so that the combined centre of gravity returns to the line or falls within the 100 mm band. That is an instruction with a bill attached, because the ballast you add is payload you had already sold to someone else.
For containerised cargo the same physics arrives in a different shape — as a front-to-back weight difference inside the box. A forty-foot container packed to the doors at one end and left light at the other is the classic version, and it is entirely legal to look at.
The bogie is the real limit
Along the wagon, the rule stops being a distance and becomes a load test. Each bogie may carry no more than half the wagon’s permitted load, and the two bogies may not differ by more than 10 tonnes.
Ten tonnes sounds generous until heavy cargo starts spending it. One dense item parked at the far end of a flat wagon gets there without any obvious drama, and so does a machine base that the factory positioned for crane access rather than for the journey. Nobody in that decision was thinking about bogies, because bogies are not part of anyone’s commercial vocabulary until a station raises the issue.
It is worth being clear about who is being tested here. The station is not judging your packing list or your invoice. It is looking at a wagon, and asking whether that wagon can run at line speed without unloading a wheel.
Your station is probably stricter
The national figure is a floor, not an operating number. Individual railway bureaux and stations commonly tighten it, and the tightening is not published in one place.
Lateral limits of 50, 70 or 80 mm turn up instead of 100 mm. For containers, front-to-back limits of 2, 3 or 5 tonnes appear depending on where you are loading. Yiwu, a major loading point for westbound traffic, works to 3 tonnes front-to-back and 50 mm across.
This is the detail that converts a rule into a commercial risk. A booking can be fully compliant with the national text and still be refused at the station that actually loads it, because the number that matters is the one the loading point enforces. It is also the number least likely to appear in any quotation, since it is not a rate and not a route.
What re-centring actually costs you
When a load fails the check, it is re-centred. The wagon does not leave until it is.
Re-centring is not a penalty and not a fine — it is work. Cargo comes off, gets repositioned, sometimes gets counterweighted, and goes back on. Three costs follow, and only one of them is money. The loaded wagon loses its place in the departure, the running time extends, and the arrival date you were given stops being a date you can rely on. Add the handling itself, and the re-work, and the fact that a wagon already loaded is the most expensive wagon to unload.
Everything about this is cheaper at the factory than at the station, which is why the loading plan deserves a look before the truck leaves, not after.
Height is a speed limit in disguise
There is a third number, and buyers almost never hear about it: the height of the loaded wagon’s centre of gravity.
General freight is limited to 2,000 mm. Tank wagons get 2,200 mm and double-stack container wagons 2,400 mm. Above the limit, the rule offers two routes — load something heavy and low to pull the centre of gravity back down, or run restricted.
The restricted option is where it becomes your problem, because the restriction is speed:
| Centre of gravity height | Line speed | Through side turnouts |
|---|---|---|
| 2,000–2,400 mm | 50 km/h | 15 km/h |
| 2,400–2,800 mm | 40 km/h | 15 km/h |
| 2,800–3,000 mm | 30 km/h | 15 km/h |
A tall, heavy load does not get refused. It gets accepted and slowed down, and a schedule built on normal line speed quietly stops applying. If you have ever been told a date and then watched it slide without anyone being able to explain why, this is one of the mechanisms that produces that experience.
The rule that travels with the wagon
One honest limit on all of the above: the 加规 governs loading inside China. Once the wagon crosses into Kazakhstan, the loading rules in force are Kazakh, then Russian, then whoever the corridor runs through next. The physics does not change at the border. The numbers do, and so does the enforcement.
What that means in practice is that a load built to the Chinese limit is not automatically a load that clears every subsequent check, and a shipment can be re-examined at a gauge change for exactly the reasons it passed at origin.
What we ask before the wagon is loaded
- The weight of each package, not only the total
- The dimensions of the heaviest single item, and where it sits in the load
- Whether anything is concentrated at one end for reasons of crane access
- The commodity, because density decides which limit bites first
- The loading point, because its local limit is the one that applies
- The height of the finished load, if the cargo is tall or top-heavy
None of these questions is difficult. All of them are cheap to answer at the factory and expensive to answer at the station.
If you are shipping containers, the working limits sit in the corridor itself, and where the load gets settled matters more than the rate agreed for it. Supplier coordination is usually where that happens, and for cargo moving beyond the railhead, multimodal transport is the piece that decides who lifts it next.
Let’s talk about what you are loading
Send us the packing list with weights per package and a photo of how the factory intends to build the load. We will tell you which limit your cargo is likely to reach, whether the loading point applies a tighter number, and whether the load needs re-building before it reaches the station rather than after.
No commitment required. Just a conversation.
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Based in: Xi’an International Trade & Logistics Park
Archer Sourcing helps European, Central Asian, and Middle Eastern businesses move cargo from China via the China-Europe Railway Express and overland corridors. We operate from Xi’an — the departure hub of the Chang’an rail service.