Open Railroad Tycoon

Rails

An OCaml remake of Railroad Tycoon (1990). Build railroads, manage trains, compete with AI rivals, and grow your empire across historical regions.

See FEATURES.md for a full list of implemented features.

Quick Start (Precompiled Releases)

Precompiled packages are available on the Releases page for Windows, Linux, and macOS:

1. Download the release archive for your OS:
   • Windows: rails-*-windows-x86_64.zip (includes all required SDL2 & codec DLLs)
   • Linux: rails-*-linux-x86_64.AppImage (or .tar.gz)
   • macOS: rails-*-macos-arm64.zip / x86_64.zip
2. Copy your original Railroad Tycoon DOS files (*.PIC, *.PAN, *.DTA) into the data/ folder next to the executable/AppImage.
3. Launch the game (rails.exe on Windows, double-click the .AppImage on Linux, or open Rails.app on macOS).

Prerequisites for Building from Source

• OCaml 5.x with opam
• SDL2 and SDL2_mixer development libraries
• Original Railroad Tycoon DOS files

Data Files

The game expects original game assets in ./data/ (or specified via --data-dir <path>).

Installation from Source

opam install . --deps-only
dune build

Running

# New game
dune exec rails

# Load saved game (can also be done via the menu system)
dune exec rails -- --load 0

# With options
dune exec rails -- --zoom 3 --shader crt-hyllian2 --adjust-ar

Command-line options

Option	Description
--load N	Load save slot 0–9
--zoom N	Display zoom, multiply the original 320x200 resolution (default: 3)
--shader NAME	Shader from shaders/*.glsl (test, crt-hyllian, vga-1080p, etc.)
--adjust-ar	Adjust aspect ratio (rectangular pixels like DOS)
--no-audio	Disable audio playback
--data-dir PATH	Custom path to folder containing original game data
--debug	Enable global debug logging
--debug-module MOD	Enable debug logging for specific module(s) (comma-separated, e.g. train,backend)
--list-debug-modules	List all available logging modules and exit

Project structure

• src/rails_lib/ — Main library
  • backend/ — Game logic (trains, stations, AI, economy)
  • ui/ — Menus, rendering, fonts, textures
  • anim/ — PANI animation format
  • utils/ — Rendering, image loading, sound
• shaders/ — GLSL shaders for display
• technical_documentation.md — Architecture and design details

Development

dune runtest
dune build @doc

License

MIT — see LICENSE.

Future

Unlike the original, the game is built with fronted-backend separation, so in theory it could be made to support >1 player.