Modes of transport
A mode is a way of moving. There are five:
- Road: cars, buses, trucks. Flexible, goes door to door. Best for short trips.
- Rail: trains on fixed tracks. Carries heavy loads over land with less fuel per tonne than trucks.
- Water: ships on seas, barges on rivers and canals. Very cheap for heavy, bulky goods, but slow.
- Air: planes. Fastest over long distances, but costly. Used for urgent, light or valuable goods.
- Pipeline: pipes for oil, gas and water. Runs all the time at low cost once built.
Transport infrastructure: roads, railways, ports and airports
Infrastructure means the fixed things that vehicles need.
Roads
Roads are graded: expressways and highways for fast long trips, local roads for access. Engineers plan the width (lanes), a smooth surface, gentle slopes and curves, drainage and bridges.
Railways
A track has two steel rails fixed on sleepers over a bed of crushed stone (ballast). Trains need gentle slopes, signals and stations. Freight corridors carry only goods trains.
Ports and harbours
A harbour is sheltered water where ships are safe. A port adds berths, cranes, container yards and links to rail and road. Deep water is needed for large ships.
Airports
An airport has runways, taxiways, aprons for parking planes, terminals for people and cargo buildings. Runways point into the usual wind.
Logistics and the supply chain
Logistics is planning and managing the flow of goods so they arrive at the right place, at the right time, in the right amount and at the right cost.
A supply chain is the full path: raw materials → factory → warehouse → distribution centre → shop → customer. A warehouse stores goods. A distribution centre sorts them and sends them out fast. The last part to the customer's door is called the last mile, and it is often the most costly part.
Barcodes, GPS tracking and computers help to plan routes and know where every parcel is.
Containers, intermodal transport and choosing a mode
A container is a steel box of standard size (about 6 m = one TEU, or 12 m). Cranes can lift it from ship to train to truck without opening it. Using two or more modes for one trip is intermodal transport.
To choose a mode, compare:
- Time = distance ÷ speed
- Cost = rate per tonne-km × mass × distance
- the type of goods (heavy, fragile, perishable, urgent)
- the route (is there a sea, a railway, an airport?) and the effect on the environment (air gives the most CO₂ per tonne-km, ships and trains the least).
Key formulas and definitions
- time = distance ÷ speed
- cost = rate per tonne-km × mass (t) × distance (km)
- tonne-km = mass (t) × distance (km)
- 1 TEU = one 20-foot (about 6 m) container
Worked examples
1. A truck travels 360 km at an average speed of 60 km/h. How long does the trip take?
time = distance ÷ speed = 360 ÷ 60 = 6 h.
2. A train carries 500 t of grain for 800 km. How many tonne-km is this?
tonne-km = 500 × 800 = 400 000 tonne-km.
3. Rate by rail is ₹1.5 per tonne-km. Find the cost to move 40 t for 1200 km.
cost = 1.5 × 40 × 1200 = ₹72 000.
4. A parcel can go 6000 km by air at 800 km/h or by sea at 30 km/h. How many hours does air save?
Air: 6000 ÷ 800 = 7.5 h. Sea: 6000 ÷ 30 = 200 h. Saving = 200 − 7.5 = 192.5 h (about 8 days).
5. Road costs 4 units and rail 2 units per tonne-km. For 30 t over 500 km, how much does rail save?
Road: 4 × 30 × 500 = 60 000. Rail: 2 × 30 × 500 = 30 000. Saving = 30 000 units (half).
6. Which mode would you choose for 50 000 t of iron ore from a mine near the coast to a steel plant across the ocean? Why?
Sea. The load is huge and heavy, it is not urgent and does not spoil, and sea has the lowest cost per tonne-km. Rail or conveyor belts can carry it from the mine to the port.
Common mistakes
- Thinking the fastest mode is always the best. Cost, load and type of goods matter too.
- Mixing up port and harbour: a harbour is sheltered water; a port is the facility with berths, cranes and links.
- Forgetting the units: speed in km/h with distance in km gives time in hours, not minutes.
- Thinking logistics is only transport. It also includes storage, packing, sorting, stock control and information.