Shanghai International Logistics Co., Ltd.
Intermodal transportation and container planning for shippers
Intermodal transportation means one shipment travels through at least two modes under a single commercial arrangement, typically road, rail, sea and inland waterway, with the cargo packed into standard containers that transfer between them without being unpacked. The defining feature is that the unit is the interface: the same box leaves the shipper's yard and arrives at the consignee's door, and each handover shifts unit, documents and responsibility.
In practice the chain is a sequence of linked contracts rather than a single shipment. Road haulage to a terminal, a rail shuttle to the port, terminal handling, the sea voyage, discharge, customs clearance and final delivery are separate processes with separate owners, and the cargo sits under three or four parties' control before it reaches the importer.
Every mode change is a handover with three objects to transfer: the physical unit, the paperwork, and liability for damage. Damage found after a rail-to-sea transfer may belong to a leg that ended hundreds of kilometres earlier, and both insurers will point at each other. Clear custody allocation, backed by handover records and condition photographs, keeps that argument from dominating the move.
Standard container geometry follows the ISO 668 and ISO 1496 series, and those standards matter because equipment compatibility follows. A 20-foot dry container is 6.06 m long, 2.44 m wide and 2.59 m high; a 40-foot is 12.19 m long; a 40-foot high cube has the same footprint with a 2.90 m height; a 45-foot high cube extends the length to 13.72 m. Corner castings take the locking devices, so any dimensioned box is handled by the same crane.
| Container type | External dimensions (L x W x H) | Tare | Maximum payload | Internal volume |
|---|---|---|---|---|
| 20 ft dry | 6.06 x 2.44 x 2.59 m | approx. 2,200 kg | approx. 28,200 kg | 33 cbm |
| 40 ft dry | 12.19 x 2.44 x 2.59 m | approx. 3,800 kg | approx. 26,700 kg | 67 cbm |
| 40 ft high cube | 12.19 x 2.44 x 2.90 m | approx. 4,000 kg | approx. 26,400 kg | 76 cbm |
| 45 ft high cube | 13.72 x 2.44 x 2.90 m | approx. 4,900 kg | approx. 25,500 kg | 86 cbm |
Compatibility is not only about the box fitting into a slot. A 40-foot container needs a 40-foot chassis; a 45-foot high cube needs a 45-foot chassis and a terminal with reach stacker and tractor capacity rated for the loaded weight. Rail adds its own constraints: platform length, bogie and axle loading limits, clearance and loading gauge. Where a 45-foot unit is not accepted on a service, the forwarder must convert to 40-foot boxes or pick another destination.
Unitisation means designing the load so the unit can be handled, stacked, secured and transported without shifting. The load plan decides how many packages enter a box, in what order, and how mass is distributed along its length. These decisions survive every handover, so a poor decision at origin is carried through rail shunting, vessel stowage and final delivery, and correcting it means unpacking at destination.
Three constraint sets govern the load plan. First, stacking: mass per unit and per pallet must respect the safe working load of the packing material and the box's rated capacity, and heavy items are loaded low and symmetrically so the centre of gravity stays within what handling equipment expects. Second, axle weights: in road haulage the combination weight and per-axle limits decide which tractor and trailer can legally collect the box, while in rail the wagon axle load is a hard cap. Third, securing: dunnage, blocking and lashing must restrain the load against accelerations.
The highest-risk errors are ignoring the difference between road and rail acceleration profiles, and assuming securing adequate for a sea leg will hold during a terminal shunt. A load stable on a ship can still creep during rail handling. Trimming loads to remove voids, blocking rather than only strapping, and verifying packed weight before sealing cost far less than damage found later.
The most common multi-leg pattern in international freight is road-rail-sea: truck from the supplier to an inland rail terminal, block train to the port or a coastal feeder, vessel across the ocean, with the inverse chain on arrival. This is attractive because the long, heavy portion of the journey moves on rail and water at lower cost per tonne-kilometre than road, and because it reduces the containers needing truck capacity at congested ports. Each extra leg adds handling events, risk and delay.
Road-rail combinations, typically truck to a rail terminal and rail to a domestic hub or inland port, are used when origin or destination sits off the rail network. The question is where the transfer should fall: rail becomes competitive at longer distances, and the transfer is only economic if the line-haul saving exceeds the terminal handling charge, the drayage cost between plant and ramp, and the delay from cut-offs. Carriers price the same movement differently depending on where the break sits.
| Mode on the leg | Relative cost per tonne-kilometre | Timing reliability | Main constraint |
|---|---|---|---|
| Road | Highest | Good, subject to driver hours | Distance and driver supply |
| Rail | Low | Moderate; slot capacity sets the spread | Network reach and axle limits |
| Sea | Lowest | Good on schedule, poor on schedule | Port congestion, sailing frequency |
| Inland waterway | Low | Moderate | Water levels and barge size |
A handover is where the container changes custody: it arrives at a terminal, is discharged from a train, vessel or trailer, checked, and released to the next leg. The interval between a container becoming available for collection and its actual pickup is dwell time, normally free for a limited period, after which demurrage charges accrue to the party named on the bill of lading.
Dwell affects total transit in a way that is easy to underestimate. A schedule built only from line-haul runtimes assumes an instant handover at each node, but in practice variance concentrates at handover points, not on the water or the rails. If a terminal works through a congestion peak, a whole train stands and every box behind it inherits the delay, and recovery can take longer because the box missed its onward connection.
A workable plan is built backward from the delivery requirement. Start with the delivery date, subtract inland drayage and terminal processing windows, subtract booked vessel and train schedules and the cut-off times at each ramp, and what remains is the production and inland-transport window at origin. The plan is then tested for feasibility: is there a sailing that accepts the booking before cut-off, does the rail service run that day, and is there drayage capacity for the container's ready time. Each leg carries a ready time, a cut-off, a booked departure and an expected availability.
Documentation transfers between carriers in the same step. Road moves on a consignment note, rail on a waybill, sea on a bill of lading, and terminal operating systems record container movements in a third structure again. The handover depends on data transferred accurately between systems that do not share a format: container number, seal number, verified gross mass, cargo description, HS codes, and consignee and notify party details. Errors in the mass declaration or commodity description surface later, at the border or discharge port. Forwarders running multi-leg chains commonly operate a control tower that reconciles carrier status messages.
Equipment imbalance arises when the flow of loaded boxes at a location is not matched by the flow of empty boxes. A port receiving more loaded imports than it exports accumulates containers; a region exporting more than it imports runs out of empties and pays for repositioning. Shortages are handled with short-term leases, local empty depots and repositioning moves, which add cost and weeks to transit. Practical responses are to book an early empty return, agree a repositioning allowance, and check empty availability.
Resilience is built into the routing rather than added afterwards. The plan should hold at least one identified alternative for each long-haul leg, such as a different sailing, rail service or truck substitution, together with the trigger conditions that would justify using it. Some decisions can be taken in advance; others depend on monitoring the chain and acting before cut-off expiry.
Performance is measured on the chain rather than on individual legs. Useful measures include door-to-door transit time and its variability, the share of shipments arriving inside the quoted window, dwell time at each terminal, handovers completed without discrepancy, and total cost per container including handling and repositioning charges. Segmenting transit time into run, handling and waiting time shows where loss occurs.
| Measure | What it shows | Typical corrective action |
|---|---|---|
| Door-to-door transit time and variance | Reliability for the customer | Adjust cut-offs and arrival buffers |
| Dwell time per terminal | Where the chain loses time | Reschedule collection, review cut-offs |
| Handling events per shipment | Exposure to damage and delay | Change the mode split |
| Document discrepancy rate | Quality of data handover | Align fields, verify once |
| Cost per container incl. empties | True chain cost | Renegotiate empty returns |
In intermodal transportation the cargo travels in a unit that stays closed and is handed over between modes without the goods being unloaded, which is what makes standardised container dimensions and sealed boxes so important. Multimodal transport is the broader term and includes combinations where goods are transferred between, for example, a vessel and a truck in break-bulk form. The intermodal label applies to containerised chains, where every handover is a transfer point to be recorded.
A twenty-foot equivalent unit is the volume equivalent of one 20-foot container, and a forty-foot equivalent unit is the volume equivalent of one 40-foot container. The units matter for pricing and vessel capacity, because capacity is quoted in TEU though vessels carry a mix of lengths. For the shipper the practical point is that a 40-foot container holds roughly twice the volume of a 20-foot but carries almost the same maximum gross weight, so dense cargo hits the weight limit first while light cargo hits the volume limit first.
Plan on the sum of the booked leg runtimes plus published cut-off and processing windows at every terminal, then add contingency at handover points rather than a flat percentage. Delay concentrates where the container changes mode, so an allowance of one working day on a road-rail-sea chain is more realistic than a proportional buffer. Quote a range and state which service it is based on, since a faster sailing with an earlier cut-off may deliver later than a slower service with a relaxed cut-off.
Liability follows the custody of the carrier at the time the damage occurred, which is why signed handover records, condition photographs and clear cut-off and free-time clauses in the carriage contracts determine who pays. In a chain with several carriers the mechanism is usually a single forwarding contract with the forwarder or main carrier, backed by claims filed with the carrier responsible for the leg. Damage recorded only at final delivery is harder to allocate.
Shanghai International Logistics Co., Ltd.