Bridges, dams, airports, and mega-projects
Typical span
30–150 m
Short to medium crossings.
Cost (per span)
$5–50M
Simplest and cheapest type.
How it works
Horizontal beams
Load transfers vertically through piers to ground.
The workhorse of bridge engineering. Most highway overpasses and railway viaducts are beam bridges. The load goes straight down through piers — simple and economical. The limiting factor is that longer spans require deeper beams, which become impractical beyond ~150 m.
Typical span
100–550 m
Sydney Harbour: 503 m.
Cost
$200M–2B
More complex than beam, less than suspension.
How it works
Arch in compression
The arch pushes outward; abutments resist that thrust.
Arches work entirely in compression — a force that stone and concrete handle beautifully. The key challenge is the horizontal thrust that pushes outward at both ends; the abutments must anchor into very solid ground. This is why arch bridges are only feasible when the geology is cooperative. The Sydney Harbour Bridge (1932) at 503 m was the world's widest long-span bridge for decades.
Typical span
200–1,100 m
Russky Bridge (Vladivostok): 1,104 m.
Cost
$500M–3B
Modern favourite for 400–800 m spans.
How it works
Cables direct to tower
Cables run straight from tower to deck — no main cable.
Cable-stayed bridges have largely replaced suspension bridges for spans up to about 1,000 m. The cables run directly from the pylons to the deck, making the system stiffer and easier to build (no complex spinning of main cables). They're faster to construct, use less steel, and are aerodynamically more predictable. The Millau Viaduct in France (the world's tallest bridge at 343 m) is a cable-stayed design.
Typical span
500–2,000+ m
Akashi Kaikyō (Japan): 1,991 m — world record.
Cost
$1–5B+
Most expensive per metre for very long spans.
How it works
Main cable + hangers
Deck hangs from vertical hangers off the catenary main cable.
Suspension bridges are the only viable option beyond ~1,000 m. The main cables form a catenary curve between towers and are anchored into massive concrete blocks onshore. The deck hangs from vertical hangers. The trade-off: flexibility. The Tacoma Narrows Bridge famously collapsed in 1940 because of aerodynamic resonance — modern suspension bridges have streamlined aerodynamic decks to prevent this. The Akashi Kaikyō (Japan, 1998) holds the world record at 1,991 m and had to be stretched 1 m during the 1995 Kobe earthquake — the main spans shifted while under construction.
Bridge type determines maximum span. No beam bridge could cross the Strait of Messina (3 km) — only a suspension bridge could. That's why bridge type isn't an aesthetic choice; it's an engineering necessity dictated by the gap to be crossed.
Passenger capacity
4–5 people
~300–400 kg of people
Cargo/boot load
~400–500 kg
Legal payload. Don't confuse with boot volume (litres).
Total vehicle weight
~1,400 kg
The car itself, empty. Payload adds on top.
Payload (small van)
~800 kg
Transit-size van. Good for pallets, furniture.
Payload (large van)
~1,200 kg
Luton / Sprinter. Used by most delivery companies.
Load volume
8–14 m³
Roughly fits a small apartment's contents.
Maximum legal payload
~24–26 tonnes
EU road limit. About 17–18 family cars' worth of weight.
Gross vehicle weight
~44 tonnes total
Truck (18t) + trailer (26t payload).
Load volume
~82–100 m³
Standard 13.6m trailer. Fits ~26 standard pallets.
Payload capacity
~103 tonnes
About 4 fully loaded HGV trucks — in one aircraft.
Range (loaded)
~8,000 km
Europe to Asia nonstop, roughly.
Cost per tonne-km
~$4–8
~50–100× more expensive than sea freight per tonne.
Container capacity
~24,000 TEU
TEU = 1 standard 20-foot container. That's 24,000 of them.
Maximum cargo weight
~165,000–185,000 t
About 7,700 loaded HGV trucks — on one ship.
Ship's own weight (empty)
~55,000 tonnes
The ship weighs ~55,000 t before loading a single container.
Cars
~4–5
Volume-limited, not weight.
Flat-screen TVs (55″)
~600–700
Weight far below the limit.
Trainers (shoes)
~20,000 pairs
Typical export load from SE Asia.
Bananas
~21 tonnes
Weight-limited. Banana ships use refrigerated reefers.
Books
~12 tonnes
~10,000 average paperbacks per tonne.
Cotton T-shirts
~40,000
Volume-limited; very light per unit.
The genius of containerisation (standardised in the 1950s–60s by Malcolm McLean) is that the same box moves from factory to ship to train to truck with no reloading. Before containers, unloading a ship in port took days and required hundreds of dockers. A modern container port unloads the same ship in 24–36 hours with a handful of crane operators.
The scale difference is staggering. One container ship carries as much as ~1,600 cargo planes or ~7,700 trucks. This is why shipping by sea is ~50–100× cheaper per tonne than air freight.
Dam height
181 m
Taller than the Eiffel Tower's observation deck.
Width
2,335 m
Over 2 km across the Yangtze gorge.
Reservoir length
~660 km
Roughly London to Edinburgh in length.
Power output
22,500 MW
World's largest power station of any kind.
Concrete used
28 million m³
~10× the Hoover Dam.
Cost
~$37B
1.4 million people relocated to build it.
The Three Gorges Dam is the single largest piece of engineering by energy output in human history. Its reservoir holds so much water that geophysicists calculated it slightly slows Earth's rotation — by about 0.06 microseconds per day. That's how much mass it holds in one place.
Gravity dam
Resists water pressure purely through its own weight. Enormous amounts of concrete. The Hoover Dam is a special variant called an arch-gravity dam — it's curved to push some load into the canyon walls. Cost-effective for wide valleys.
Arch dam
Thin curved wall that transfers water pressure sideways into the valley walls — like an arch bridge on its side. Uses far less concrete than a gravity dam. Only viable in narrow valleys with extremely hard rock. The 285 m Jinping-I in China is the world's tallest arch dam.
Earthfill / rockfill dam
The most common type worldwide. A compacted mound of earth, rock, and clay with a watertight core. Nurek Dam in Tajikistan (300 m) is the world's tallest earthfill dam. Cheap to build but can't have water flowing over the top — overtoppling causes catastrophic failure.
Longest bridge (total)
Danyang–Kunshan Grand Viaduct
164 km — high-speed rail, China (2011). Shanghai–Beijing line.
Longest bridge main span
Akashi Kaikyō Bridge
1,991 m — suspension, Japan (1998).
Tallest bridge
Millau Viaduct
343 m above the Tarn valley floor — cable-stayed, France (2004).
Longest road tunnel
Lærdal Tunnel
24.5 km — Norway (2000). Includes rest caverns with coloured lighting.
Longest undersea tunnel
Seikan Tunnel
53.9 km — Japan (1988). 23 km undersea. Channel Tunnel is 38 km undersea.
Tallest dam
Jinping-I Dam
305 m — arch dam, China (2013). Taller than the Eiffel Tower.
Largest power station
Three Gorges Dam
22,500 MW — China (2012 at full capacity). Hydroelectric.
Deepest mine
Mponeng Gold Mine
~4 km deep — South Africa. Rock temperature reaches 60°C without cooling.
Longest railway
Trans-Siberian Railway
9,289 km — Moscow to Vladivostok. 7 time zones. ~6 days non-stop.
Busiest container port
Port of Shanghai
~49 million TEU/year (2023). Handles ~1 container every 0.6 seconds.
Optimism bias
Planners systematically underestimate costs and overestimate benefits to get projects approved. Researcher Bent Flyvbjerg found that 9 out of 10 large infrastructure projects go over budget.
Unknown unknowns
You can't fully survey underground conditions until you dig. Unexpected geology — rock faults, groundwater, archaeological remains — is the most common cause of delay and cost escalation in tunnels and foundations.
Scope creep + politics
Projects that begin construction are politically almost impossible to cancel, regardless of cost growth. This creates perverse incentives: underestimate to start, then expand once underway.
Daily passengers
~287,000
About the entire population of Newcastle boarding planes every day.
Daily flights
~2,700
One takeoff or landing every ~32 seconds.
Runways
5
Two pairs of parallel runways + 1 dedicated to smaller aircraft.
Terminal length
~2.4 km
Underground trains connect the concourses.
Employees on-site
~63,000
Larger than many cities' entire workforces.
Airlines served
~150
Primary hub for Delta Air Lines (~75% of traffic).
ATL has been the world's busiest airport almost continuously since 1998. Its dominance comes from geography (equidistant from the US East Coast and Midwest) and Delta's "hub-and-spoke" model, where virtually every Delta domestic flight connects through Atlanta. The practical consequence: if you're flying anywhere in the eastern USA, there's a good chance you're connecting through ATL whether you intended to or not.
APM = Automated People Mover (underground train). Large airports separate the terminal (check-in, security, retail) from the gates via APM trains — walking the full gate concourse of ATL would be ~2.4 km.
A greenfield major airport is one of the most expensive single infrastructure projects a government can undertake — comparable to a nuclear power plant but more politically popular. The per-passenger cost of a new airport is around $80–120 per annual passenger of designed capacity. A 100M pax/year airport therefore costs roughly $8–12B just for the airport itself, before roads, rail links, or a second runway.
Daily passengers
~3.5 million
More than the entire population of Chicago passing through daily.
Train lines served
12 lines
JR, Tokyo Metro, Toei, Odakyu, Keio, Seibu — plus long-distance.
Exits
200+
Guinness World Record for most exits of any station.
Underground floor area
~10 km² network
The underground corridors are so complex a tourist map is essential.
Daily trains through
~3,000
JR East alone operates ~1,500 train services per day through Shinjuku.
Retail on-site
~200 shops
The station is also a major shopping destination, not just a transit hub.
Shinjuku is in a different category from everything else on this list. Its 3.5 million daily figure is not a typo — it's more than the combined daily total of all five London terminus stations. The reason is Japan's uniquely dense commuter rail network, where a single station serves as the convergence point for 12 separate rail lines serving Tokyo's western suburbs. At peak hour, a train arrives or departs every 30–40 seconds on multiple platforms simultaneously.
Daily passenger movements. The world's busiest train station (Shinjuku, 3.5M/day) handles about 12× more passengers than the world's busiest airport (ATL, ~287K/day). Rail density in Tokyo is simply in a different category.
Gare du Nord handles ~1.3M passengers per day — making it the busiest station outside Asia. It is the only station in the world where you can board a Eurostar (international high-speed), a TGV (domestic high-speed), a Transilien commuter train, a Paris Métro, and an RER suburban express all within a few hundred metres. Its geographic position directly above the Channel Tunnel link makes it structurally irreplaceable for European rail. Heathrow Airport by comparison handles ~217,000 passengers per day — about 1/6th of Gare du Nord.
1. A news article says a new bridge will cost "$800 million." Is that cheap, average, or expensive for a bridge?
2. You want to move 500 tonnes of cargo from Europe to Japan. A ship takes 30 days. A plane takes 12 hours. What's the main reason almost everyone chooses the ship?
3. A removal company says their van can carry "up to 1 tonne." You're moving a 2-bedroom flat. Is one van enough?
4. A large container ship carries ~175,000 tonnes. It crosses the Pacific in about 14 days. How many HGV trucks would it take to carry the same load on land?
5. A new airport is announced with a capacity of 60 million passengers per year. A news article says it will cost $7 billion. Is that cheap, about right, or expensive for an airport of that size?
6. A new nuclear power plant in the UK is announced with a budget of £20 billion and a 10-year build time. Based on infrastructure history, what should you expect?
7. The Millau Viaduct in France is 343 m tall and carries the A75 motorway. It cost €394 million (2004). Is that cheap, normal, or expensive for a major bridge?