Rail Switch 🚂

Ride and switch · Vanilla rails just connect · No mixins · 220 bps tested

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Rail Switch adds two Y-shaped switch rails to Minecraft Java 26.2 (Fabric). Ride a minecart and hold Left or Right (default A / D) before the switch and the cart takes that branch; with no input the cart follows wherever the points currently are. Vanilla rails recognise the block and connect to it automatically.

The mod ships no mixins and does not overwrite vanilla minecart methods. It updates switch-rail block states and reads vanilla player-input data; its behavior depends on Minecraft's new minecart physics and rail-state handling. Avoiding mixins removes one common source of conflicts, but does not guarantee compatibility with every rail or physics mod. Compatibility has been tested alongside highspeed-rail at 220 bps; other combinations are unverified.

Feedback and support: Sign in to GitHub before creating an issue. When signed out, GitHub may show “Issue creation is restricted in this repository.” Commercial-license inquiries can also use the email address on the author's GitHub profile.

🌟 Key Features

🚦 Press to switch left_switch_rail diverges left when the rider holds Left (default A); right_switch_rail diverges right on Right (default D). An empty cart, a non-player rider or no input never throws the points for that cart — it follows wherever they currently are.	🔀 Vanilla rails just connect The block passes vanilla's isRail checks and enters the minecraft:rails tag, so neighbouring vanilla rails adjust their shape to meet it. It drops like a vanilla rail when its support is broken.
🧩 No mixins No patch to AbstractMinecart or NewMinecartBehavior. Switching changes the rail block state and lets vanilla's new physics handle the turn; compatibility with other physics mods depends on each mod and should be tested.	⚡ High-speed ready Look-ahead distance scales with cart speed, and a 0.5 s key-memory window lets a long press well before the points still land. Verified alongside highspeed-rail[1] at 220 bps.
🛤️ Trailing moves merge Coming from the branch side, the cart merges into the points end instead of derailing or stopping. Can be configured to stop instead.	🎛️ Configurable Six options in config/rail_switch.json: look-ahead, key memory, lever sound, legacy-physics behaviour, trailing behaviour, and a debug log.

📦 Quick Start

Requirements

Requirement	Detail
Minecraft	Java Edition 26.2, Fabric
Fabric Loader	>= 0.19.0
Fabric API	required
Java	>= 25
New minecart physics	must be enabled (minecart_improvements). Without it the switch degrades to a plain rail and logs one warning.
Sides	client and server both need the mod

Install

Download the jar from the latest release — or build it yourself, see DEVELOPING.md.

The mod adds blocks, which is content — a client without it will see broken blocks. Install the same version on both sides:

<profile>/mods/            (client)
├── fabric-api-*.jar
└── rail-switch-1.2.1-fabric-26.2.jar

<server>/mods/             (server, same file)
├── fabric-api-*.jar
└── rail-switch-1.2.1-fabric-26.2.jar

• Single player: drop it into your client mods/ — the integrated server loads it too.
• Server: put it in the server mods/ and have every player add it to their client mods/.
• Install the mod on the server before loading a world that already contains switch rails, otherwise those blocks cannot be resolved.

Place a switch

A switch rail only acts as a switch with three connected directions: both ends of the straight track plus one branch end. There is a Rail Switch creative tab (v1 ships no crafting recipe).

        north (branch)
        │
  ──────┼──────      straight: east–west
  west  │  east      branch: north
        │

🎮 Usage

1. Ride a minecart and hold Left or Right (default A / D) before the switch.
2. On a matching switch rail the cart takes that branch; with no input it follows wherever the points currently are — the switch does not spring back, it keeps the position it was last thrown to until a cart comes through.
3. There is a 0.5 s (10 tick) memory window after you release — but at speed, press early: at 200 bps a cart covers 10 blocks per tick, so hold the key 20–60 blocks ahead.

The arrow keys are unbound by default, and one action can only have one key. To use them, rebind Left / Right in Options → Controls; the mod reads the key binding, so rebinding just works.

⚙️ Configuration

config/rail_switch.json is created on first launch:

Field	Default	Meaning
lookaheadBlocks	0	Look-ahead distance in blocks; 0 = automatic (speed × 2 + 2, clamped to 2–64)
inputMemoryTicks	10	Key memory window in ticks
switchSound	true	Play the lever sound when the points move
requireNewPhysics	true	Disable switching in dimensions without the new minecart physics
trailingBehavior	merge	Approaching from the branch: merge into the points end, or stop
debugLog	false	Log every set / freeze decision (troubleshooting)

📄 License

This project is licensed under the PolyForm Noncommercial License 1.0.0 (SPDX identifier PolyForm-Noncommercial-1.0.0).

• The full license text governs: LICENSE — official text at https://polyformproject.org/licenses/noncommercial/1.0.0. This section is a readable summary, not a modification of, or a substitute for, the license terms.
• Free for noncommercial use: personal play, study, research, testing, educational institutions, charities.
• Commercial use requires a separate license from the author: open an issue, or email the address on the author's GitHub profile.
• Redistribution duty: any redistribution must carry the full license text (or its official URL) plus the notice line below.

Required Notice: Copyright (c) 2026 Hardware Alexander (https://github.com/ResAlexander/rail-switch)

This is a source-available license, not an OSI-approved open-source license, so paid servers and paid modpacks are outside the free-use scope.

🛠️ Development

Development details live in DEVELOPING.md.

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^[1] highspeed-rail: https://modrinth.com/mod/highspeed-rail

_{NOT AN OFFICIAL MINECRAFT MOD. NOT APPROVED BY OR ASSOCIATED WITH MOJANG OR MICROSOFT.}