Port Skylines

Design a container terminal on a 4 m grid, then watch every box move through it.

_{The Mega port: 6 berths, 18 STS cranes, 80 RTG yard blocks holding 20,000 boxes, 12 gates and two rail yards, every box simulated.}

Play · Features · How a box moves · Progression · Roadmap · Develop

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Port Skylines is a port-building game in the spirit of city builders. You lay out berths, roads, gates and yard blocks; shipping lines bring weekly calls; and an honest, deterministic simulation moves each container by crane, tractor, yard machine, lorry and train. Your throughput is whatever your layout earns.

Note

Port Skylines is in active development. Phases M1 to M5 are complete. M6 (scale and on-dock rail) has all of its features in, and is waiting on its performance target before it is tagged. See Roadmap.

Features

Build on a 4 m grid Click a berth onto the coast: feeder (200 m), Panamax (300 m) or Neopanamax (400 m). Each brings its own road and marked crane spots. Draw roads from the highway, then drag gates and yard blocks out along them.	Work ships at true scale STS cranes stand on 30.5 m rails and reach across the widest ship their kind serves. Deck stacks are drawn box by box, as many rows across as the ship class carries. Tractors shuttle each box to a handover slot.
Take trucks off the road with rail RMG rail yards load and unload trains at their sidings. Trains run to a timetable, book the level crossings they cover, and take the imports booked to rail. A rail discount shifts each line's modal split.	Run it as a business Lines offer weekly services for berth windows, and the week is planned berth by berth with clashes in red. Every dollar goes through the ledger, and money per crane move shows income and cost by line and by terminal.

Everything else in the simulation

System	What it does
Traffic	Lanes on 0°, 45° and 90° roads, one vehicle per cell, junctions that form by themselves, and gate queues that back up onto the public road
Yard	Reach stackers, RTGs and RMGs stack to their own heights, dig out buried boxes, and work handover slots in turn
Gates	Manual, OCR and automated gate levels, one-way or two-way, with check-in times from the data
Contracts	Three shipping lines with liveries, reputation, berth windows, late calls and cancellations
Hinterland	Every box has an off-map origin or destination, reached by road or by rail, with demand that grows with each milestone
Reefers	Plugged in reefer blocks, drawing 4 kW (7 kW on hot days), billed on the day's peak, and fined when left unplugged
Special cargo	Rush imports fined when their call is late; dangerous goods only in their own blocks, kept apart from the rest
Economy	Move prices, storage fees past free days, upkeep by terminal, loans, a bailout, and an end-of-year scoreboard
Ships	Feeder, Panamax and Neopanamax, gated by channel depth, berth length and crane outreach; dredging deepens the channel
Saves	Versioned save files that migrate every older version, each one kept as a test fixture

How a box moves

flowchart LR
    Ship([Ship at berth]) -->|STS crane| Tractor
    Tractor -->|handover slot| Yard[(Yard block)]
    Yard -->|RTG / reach stacker| Lorry
    Yard -->|RMG| Train([Train])
    Lorry -->|gate check-out| Highway([Highway])
    Highway -->|gate check-in| Export[(Export block)]
    Export -->|tractor| Ship
    classDef sea fill:#1f6feb,stroke:#1f6feb,color:#fff
    classDef land fill:#2ea043,stroke:#2ea043,color:#fff
    class Ship,Train sea
    class Highway land

Loading

Imports leave the ship by STS crane onto a tractor, which hands them over at a yard block slot. They wait there for their dwell time, then go out by lorry through the gate or by train from an RMG siding. Exports run the same chain backwards. Every step is a timed job in a fixed-tick, deterministic sim, so the same commands always give the same port.

Progression

Milestones count the TEU moved across the quay. Each one unlocks new content and raises hinterland demand.

Milestone	TEU	Unlocks
⚓ Harbour	0	Contracts with shipping lines · feeder services · reach stackers · the ledger
🏗️ Terminal	200	Loans · RTG cranes · OCR gate portals
🚢 Gateway	600	Land · dredging · Panamax services · automated gates · rail track and RMG yards
🌐 Hub	1,500	Neopanamax services and berths · wide STS cranes

A guided start walks a new port from its first berth to its first worked ship on the $20,000 start money. Creative mode lifts the money limit.

Play

You need Godot 4.7.2 (the standard build, not .NET). Open project.godot and press F5.

Input	Action
Left click / drag	Place a berth, draw a road, drag an area along a road, place a crane, bulldoze
W A S D / arrow keys	Pan
Q / E	Rotate
Mouse wheel	Zoom
1 to 8	Roads, Quay, Cranes, Yard, Gate, Land, Bulldoze, Inspect
Esc	Game menu; also stops following a box

Tip

Want to see everything at once? In a debug run (from the editor), Menu → Mega port (debug) loads the big test port with every milestone reached, rail running and the yards full.

Windows build

Every pushed tag makes CI build PortSkylines-<tag>-windows.zip as a workflow artifact. export_presets.cfg has one preset, Windows, with the shader baker on so shaders compile at export rather than stuttering on first use. CI exports headless, without a GPU, so it skips the baker; for a baked build, export from the Godot editor on a machine with a GPU:

godot --export-release "Windows" build/windows/PortSkylines.exe

Roadmap

	Phase	Status
✅	M1 Foundations: fixed ticks, versioned saves, data-driven content	Done
✅	M2 A real terminal loop: berth windows, crane rates, yard, gate	Done
✅	M3 Contracts, economy and progression	Done
✅	M4 Vertical slice and art	Done
✅	M5 Roads and areas: the 4 m grid, lanes and terminals	Done
🟧	M6 Scale and on-dock rail: endgame scale, rail, reefers, Neopanamax	Features in; performance target open
⬜	M7 CS2-style cost routing	Planned
⬜	M8 The whole port	Planned
⬜	M9 Barge and feeder transhipment	Planned
⬜	M10 Events and regulations	Planned
⬜	M11 Policies, rules and automation	Planned
⬜	M12 Release 1.0 on Windows	Planned

Important

M6's exit target is 60 fps at 1080p on a GTX 1660-class PC with the endgame port at 1×. Today the sim tick at that load is 32 ms on a 2.1 GHz cloud CPU, so it is not met yet. The measurements and the options are in docs/perf.md.

The research behind the plan, from rivals to real terminal maths, is in docs/ROADMAP.md.

Develop

The sim is plain typed GDScript with no engine nodes. It changes only through PortSim.apply(command) and PortSim.tick(), and the view only reads it. That keeps it deterministic: a replay test checks that the same command log gives the same state hash at 1, 3 and 6 ticks a frame.

flowchart LR
    Input([Mouse & keys]) --> Main[main.gd]
    Main -->|commands| Sim[PortSim]
    Main -->|tick| Sim
    Data[(data/base/*.json)] --> Sim
    Sim -.->|read only| View[WorldView]
    Sim -.->|read only| HUD[Hud]
    Sim <-->|versioned| Saves[(SaveFile)]

Loading

Tests

godot --headless --import
for t in tests/test_*.gd; do timeout 300 godot --headless --script "res://$t"; done

Each test prints tests: N failure(s) and exits non-zero on failure, and CI also fails on any SCRIPT ERROR or ERROR line. The suite covers the rules, roads and traffic, rail, cargo, berths, the guided start, replay determinism, every save fixture and a two-day soak with invariants checked every tick. See tests/README.md for each test, the fixtures and the benchmarks.

Content

Every tunable number lives in data/base/*.json, which covers rules, ships, berths, equipment, roads, areas, lines and the hinterland. The loader checks each key's type and fails with the file and key named. All keys are documented in docs/content.md.

Project layout

Path	Role
art/, assets/	Blender sources (Git LFS) and the .glb models exported from them; see art/README.md
data/base/*.json	Every tunable number; keys in docs/content.md
scripts/sim/port_sim.gd	The sim's state: money, ships, cranes, boxes, vehicles, trains, land, upkeep and KPIs
scripts/sim/area_flow.gd	Ships at berths, cranes, tractors and lorries moving boxes by slots and machine jobs
scripts/sim/rail_flow.gd, train.gd	Trains on their timetable, RMG sidings and level crossings
scripts/sim/road_net.gd, lane_graph.gd, lane_traffic.gd	Roads and track at 0, 45 and 90°, the lanes routed over them, and one vehicle per cell
scripts/sim/areas.gd, area_layout.gd	Areas dragged along roads, grouped into terminals, and how each lays itself out
scripts/sim/handovers.gd, machines.gd, area_stacks.gd	Handover slots, yard machines' jobs and the stacks in yard blocks
scripts/sim/contracts.gd, ledger.gd, finance.gd	Lines and services, the books, loans and the bailout
scripts/sim/content.gd, save_file.gd	Loading and checking the data; versioned saves and their migrations
scripts/world_view.gd	Draws the sim in 3D with MultiMeshes; reads it, never changes it
scripts/hud.gd, hud_details.gd, inspect.gd, guide.gd	Toolbar, panels, Inspect and the guided start
scripts/main.gd	Wires them together and turns frame time into ticks and clicks into commands
bench/	The sim bench, the endgame port and save, and the profiler

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_{Built with Godot. GIFs are captured from the game itself, with the Compatibility renderer.}