Swiss Transport

🇨🇭 Part of the Swiss Public Data MCP Portfolio

🚆 swiss-transport-mcp

License: MIT Python 3.11+ MCP Data Source

MCP server connecting AI models to the Swiss public transport system – journey planning, real-time departures, disruptions, occupancy, ticket prices, train formations and open data from opentransportdata.swiss.

🇩🇪 Deutsche Version

Demo

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Overview

swiss-transport-mcp gives AI assistants like Claude a complete Swiss travel information system – not just timetables, but also real-time disruption alerts, occupancy forecasts, ticket prices, and a full train formation view. All accessible through a single, standardised MCP interface.

The various APIs at opentransportdata.swiss speak different protocols – OJP 2.0 (XML/SOAP), SIRI-SX (XML), REST/JSON. This server translates everything into clean JSON for the AI model, acting as a multilingual protocol interpreter.

Anchor demo query: "Plan a school trip for 25 students from Zurich to the Technorama in Winterthur – check for disruptions and find the best departure." → More use cases by audience →

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Features

• 🗺️ Journey planning (A → B with transfers, duration, transport mode) via OJP 2.0
• 🕐 Real-time departures with delays and platform information
• 🔍 Stop search by name or coordinates
• 🚨 Live disruption alerts (cancellations, closures) via SIRI-SX
• 📊 Occupancy forecasts for trains (SBB, BLS, Thurbo, SOB)
• 💰 Ticket prices including class selection
• 🚃 Train formation – coaches, classes, amenities, accessibility
• 📦 Open data catalogue – ~90 transport datasets via CKAN
• 🔑 Graceful degradation – server starts with core tools even without optional API keys
• ☁️ Dual transport – stdio for Claude Desktop, Streamable HTTP/SSE for cloud deployment

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Prerequisites

• Python 3.11+
• A free API key from api-manager.opentransportdata.swiss (subscribe to OJP 2.0 as minimum)
• Optional: additional keys for SIRI-SX, Occupancy, Formation, OJP Fare

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Installation

# Clone the repository
git clone https://github.com/malkreide/swiss-transport-mcp.git
cd swiss-transport-mcp

# Install
pip install -e .

Or with uvx (no permanent installation):

uvx swiss-transport-mcp

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Quickstart

# Set the minimum required key (OJP core tools)
export TRANSPORT_API_KEY=your_key_here

# Start the server (stdio mode for Claude Desktop)
swiss-transport-mcp

Try it immediately in Claude Desktop:

"What are the next departures from Zurich Stadelhofen?" "How do I get from Wädenswil to Bern by train?"

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Configuration

Environment Variables

Variable	API	Required
TRANSPORT_API_KEY	Unified key for OJP + CKAN	✅ (or individual keys)
TRANSPORT_OJP_API_KEY	OJP 2.0 Journey Planner	Optional (override)
TRANSPORT_CKAN_API_KEY	CKAN data catalogue	Optional (separate subscription)
SIRI_SX_API_KEY	Disruption alerts (SIRI-SX)	Optional
OCCUPANCY_API_KEY	Occupancy forecast	Optional
FORMATION_API_KEY	Train formation	Optional
OJP_FARE_API_KEY	Ticket prices (OJP Fare)	Optional

APIs without a key are silently disabled – the server starts fine with just the 6 core tools.

Operational / security variables:

Variable	Effect	Default
MCP_ENV / ENV	Process environment. Must be dev/development/local/test to allow disabling TLS verification.	(unset → production)
TRANSPORT_SSL_VERIFY	Set to false to disable TLS certificate verification. Honoured only when MCP_ENV marks a dev environment – otherwise the request is ignored and verification stays on.	true
TRANSPORT_CKAN_URL	Override the CKAN base URL. Must stay on the egress allow-list (*.opentransportdata.swiss); off-site overrides are refused.	https://api.opentransportdata.swiss/ckan-api
MCP_CORS_ORIGINS	Comma-separated list of browser origins allowed to call the HTTP transport. Use * to allow any origin (not recommended). The Mcp-Session-Id header is exposed to these origins.	https://claude.ai
LOG_FORMAT	json for structured logs (RFC 5424 severity); anything else for human-readable text. Always written to stderr.	text
OTEL_TRACES_ENABLED	1 to enable OpenTelemetry tracing (requires the otel extra: pip install 'swiss-transport-mcp[otel]'). No-op otherwise.	(off)
MCP_STATELESS	1 to run the Streamable HTTP transport statelessly — no server-side session state, so instances need no sticky load balancing. Recommended for horizontal scale-out.	(off → stateful)
MCP_ALLOWED_HOSTS	Comma-separated list of the names this server is reachable under, port included where it matters (e.g. fahrplan.example.ch:8080). Requests arriving under any other Host are rejected with 421; loopback stays allowed so container health checks keep working. Unset on a non-loopback bind, the check is off and a warning is logged.	(unset → off)

🔒 Egress allow-list: all outbound requests are restricted to https:// on opentransportdata.swiss hosts. Any other host is refused before a request is sent (SSRF / egress hardening).

Claude Desktop Configuration

Minimal (core tools only):

{
  "mcpServers": {
    "swiss-transport": {
      "command": "swiss-transport-mcp",
      "env": {
        "TRANSPORT_API_KEY": "your_key_here"
      }
    }
  }
}

Full (all 11 tools):

{
  "mcpServers": {
    "swiss-transport": {
      "command": "swiss-transport-mcp",
      "env": {
        "TRANSPORT_API_KEY": "your_ojp_key_here",
        "SIRI_SX_API_KEY": "your_siri_key_here",
        "OCCUPANCY_API_KEY": "your_occupancy_key_here",
        "FORMATION_API_KEY": "your_formation_key_here",
        "OJP_FARE_API_KEY": "your_fare_key_here"
      }
    }
  }
}

Config file locations:

• macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
• Windows: %APPDATA%\Claude\claude_desktop_config.json

Cloud Deployment (Streamable HTTP)

For use via claude.ai in the browser (e.g. on managed workstations without local software). The cloud transport is Streamable HTTP (MCP_TRANSPORT=streamable-http, endpoint /mcp). SSE (/sse) is still supported but deprecated.

MCP_TRANSPORT	Use	Endpoint
stdio (default)	Local Claude Desktop subprocess	–
streamable-http (or http)	Cloud / container (recommended)	/mcp
sse	Legacy browser transport (deprecated)	/sse

Docker (recommended):

# Build + run with explicit resource limits (see docker-compose.yml)
TRANSPORT_API_KEY=xxx docker compose up --build
# → http://127.0.0.1:8000/mcp

The image is a multi-stage build running as a non-root user; docker-compose.yml adds read_only, no-new-privileges and memory/CPU/PID limits.

Render.com:

1. Push/fork the repository to GitHub
2. On render.com: New Web Service → connect GitHub repo (Docker runtime)
3. Set env MCP_TRANSPORT=streamable-http and MCP_HOST=0.0.0.0
4. In claude.ai under Settings → MCP Servers, add: https://your-app.onrender.com/mcp

💡 "stdio for the developer laptop, Streamable HTTP for the cloud."

Scaling horizontally: run with MCP_STATELESS=1. In stateless mode the server keeps no per-session state, so any instance can serve any request and a plain round-robin load balancer suffices — no sticky sessions / Mcp-Session-Id affinity required. If you need stateful streaming instead, route by Mcp-Session-Id at the edge LB (e.g. HAProxy stick-tables) so each session stays pinned to one instance.

⚠️ Binding: In a network transport the server binds to 127.0.0.1 by default so a locally started server is not exposed to your whole network (e.g. public Wi-Fi). Set MCP_HOST=0.0.0.0 only in a container/cloud environment where binding to all interfaces is intended (the Docker image does this for you).

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Available Tools

Core Tools (OJP 2.0 / CKAN)

Tool	Description	Data Source
transport_search_stop	Search stops/stations by name	OJP 2.0
transport_nearby_stops	Find nearby stops by coordinates	OJP 2.0
transport_departures	Real-time departure board with delays & platforms	OJP 2.0
transport_trip_plan	Plan journey A → B with transfers, duration, mode	OJP 2.0
transport_search_datasets	Search open data catalogue (~90 datasets)	CKAN¹
transport_get_dataset	Get full details of a specific dataset	CKAN¹

¹ CKAN tools require a separate subscription in the API Manager.

Extension Tools (optional API keys)

Tool	Description	Data Source
get_transport_disruptions	🚨 Live disruptions, cancellations, line closures	SIRI-SX
get_train_occupancy	📊 Occupancy forecast for specific trains	Occupancy JSON
get_ticket_price	💰 Ticket prices for connections	OJP Fare
get_train_composition	🚃 Train formation, classes, accessibility	Formation REST
check_transport_api_status	🔍 Health check for all configured APIs	All

Example Use Cases

Query	Tool
"Next trains from Zurich Stadelhofen?"	transport_departures
"Plan a trip for 25 students from Zurich to Winterthur Technorama"	transport_trip_plan
"Any disruptions between Zurich and Bern?"	get_transport_disruptions
"How full is IC 1009 today?"	get_train_occupancy
"What does a ticket from Wädenswil to Bern cost?"	get_ticket_price
"Does IC 708 have a dining car?"	get_train_composition
"Which stops are near Langstrasse 100?"	transport_nearby_stops

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Architecture

┌─────────────────┐     ┌───────────────────────────┐     ┌──────────────────────────┐
│   Claude / AI   │────▶│   Swiss Transport MCP     │────▶│  opentransportdata.swiss  │
│   (MCP Host)    │◀────│   (MCP Server)            │◀────│                          │
└─────────────────┘     │                           │     │  OJP 2.0  (XML/SOAP)     │
                        │  11 Tools · 2 Resources   │     │  SIRI-SX  (XML)          │
                        │  Stdio | SSE              │     │  CKAN     (REST/JSON)    │
                        │                           │     │  Occupancy(REST/JSON)    │
                        │  Core:                    │     │  Formation(REST/JSON)    │
                        │   api_client + ojp_client │     │  OJP Fare (XML/SOAP)     │
                        │  Extensions:              │     └──────────────────────────┘
                        │   siri_sx, occupancy,     │
                        │   ojp_fare, formation     │
                        └───────────────────────────┘

Infrastructure Components

Component	Metaphor	Function
RateLimiter	Bouncer	Limits API calls per time window
SimpleCache	Whiteboard	Caches responses for repeated queries
APIClient	Switchboard	Handles auth, redirects, errors centrally
APIConfig	Business card	Key, URL, limits per API

Caching Strategy

API	Cache TTL	Rationale
SIRI-SX	120s	Disruptions don't change every second
Occupancy	300s	Forecasts are day-based
Formation	600s	Train composition is stable for the day
OJP Fare	1800s	Prices rarely change intraday

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Project Structure

swiss-transport-mcp/
├── src/swiss_transport_mcp/        # Main package
│   ├── server.py                   # FastMCP server, tool definitions
│   ├── api_client.py               # Core OJP + CKAN client
│   ├── ojp_client.py               # OJP 2.0 XML/SOAP parser
│   ├── api_infrastructure.py       # RateLimiter, SimpleCache, APIClient
│   ├── siri_sx.py                  # Disruption alerts
│   ├── occupancy.py                # Occupancy forecasts
│   ├── ojp_fare.py                 # Ticket prices
│   └── formation.py                # Train formation
├── tests/
│   └── test_server.py              # Unit + integration tests
├── .github/workflows/ci.yml        # GitHub Actions (Python 3.11/3.12/3.13)
├── claude_desktop_config.json       # Example Claude Desktop config
├── pyproject.toml
├── CHANGELOG.md
├── CONTRIBUTING.md
├── LICENSE
├── README.md                        # This file (English)
└── README.de.md                     # German version

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Safety & Limits

• Read-only: All tools perform read-only requests (HTTP GET / OJP XML POST for queries only) — no data is written, modified, or deleted on any upstream system.
• No personal data: Journey queries are transient and not stored by this server. The APIs return scheduled timetable and real-time operational data. No personally identifiable information (PII) is processed or retained.
• Rate limits: opentransportdata.swiss enforces per-key rate limits (documented in the API Manager). The server's built-in RateLimiter (SIRI-SX: 2 req/min, Formation/OJP Fare: 5 req/min) stays within these bounds automatically. Use the limit parameters conservatively for bulk queries.
• API key required: A free key from api-manager.opentransportdata.swiss is mandatory. Keys are bound to your account's subscription — only subscribe to APIs you intend to use.
• Data freshness: Real-time tools (departures, disruptions, occupancy) reflect the upstream source at query time. The server caches responses for short TTLs (120s–1800s) to reduce API load — see the Caching Strategy table above.
• Terms of service: Data is subject to the ToS of opentransportdata.swiss. OJP, SIRI-SX, and the CKAN catalogue are published under open licences (ODbL / CC BY 4.0) for non-commercial and research use.
• No guarantees: This server is a community project, not affiliated with the Federal Office of Transport (BAV/OFT) or SBB. Availability depends on upstream APIs.

Before you install (consent)

Adding this server to your MCP client lets the connected AI model issue Swiss public-transport queries on your behalf, using your opentransportdata.swiss API key, and make outbound HTTPS requests to opentransportdata.swiss. Nothing is written upstream and no PII is stored, but you should review the tool list above and confirm you are comfortable granting that access before configuring the server.

Running the HTTP transport safely (no built-in auth)

The server has no authentication of its own. When you run the Streamable HTTP transport (MCP_TRANSPORT=streamable-http), the MCP SDK issues a cryptographically random Mcp-Session-Id per session, but there is no user identity bound to it. Therefore:

• Do not expose a no-auth instance directly to the public internet. Put it behind an authenticating reverse proxy (OAuth2 proxy, mTLS, or your platform's access control), or restrict it to a trusted network.
• Keep the default MCP_HOST=127.0.0.1 for local use; only bind 0.0.0.0 inside a controlled container/cloud environment (see Deployment).
• Scope MCP_CORS_ORIGINS to the origins you actually trust.
• Set MCP_ALLOWED_HOSTS whenever you bind beyond loopback. It guards against DNS rebinding: a page on your network resolves its own hostname to this server's address and then talks to it from the browser. CORS does not stop that — from the browser's point of view the request is same-origin — and neither would a token, since the attacking page runs in a context that holds one. Only the Host check does. Left unset the check stays off, which is the right default only when something in front of the server validates Host.

See SECURITY.md for the full security posture and the accepted-risk decisions (gateway-level controls).

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Known Limitations

• OJP Fare: Discounts (Halbtax, GA, regional passes) are not always reflected
• Formation: Stop-based data is only available for TODAY (real-time dependency)
• Occupancy: SBB, BLS, Thurbo and SOB only – no private railways
• SIRI-SX: Returns ALL Swiss disruptions → use the filter_text parameter
• CKAN: Requires a separate subscription in the API Manager

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Testing

# Unit tests (no API key required)
PYTHONPATH=src pytest tests/ -m "not live"

# Integration tests (API key required)
TRANSPORT_API_KEY=xxx pytest tests/ -m "live"

Where the test data comes from

All four upstream APIs need a Bearer token from the opentransportdata.swiss API-Manager, so CI cannot record a real response — measured and kept in tests/fixtures/upstream_auth_probe.json. The XML payloads in the test modules are therefore hand-written, not recorded, and cannot refute the production code: both come from the same reading of the docs, and where both are wrong they are wrong together.

What can be recorded is the contract. OJP 2.0 is a CEN standard (CEN/TS 17118) with a public XML schema, and tests/fixtures/ojp_2_0_contract.json is a dated index derived from it — element names, the structures this server builds on, the enumerations it sends as values, plus the SHA-256 of every schema file read. tests/test_ojp_contract.py holds the requests and parsers against it. The schema itself is deliberately not vendored: the source repository carries no licence file.

python scripts/record_fixtures.py          # re-record
python scripts/record_fixtures.py --check  # recompute against the pinned tag

Source, date, selection rule and hashes: tests/fixtures/PROVENANCE.md.

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Changelog

See CHANGELOG.md

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Contributing

See CONTRIBUTING.md

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Security

See SECURITY.md (Deutsch) for the security posture and how to report a vulnerability.

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License

MIT License — see LICENSE

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Author

Hayal Oezkan · github.com/malkreide

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Credits & Related Projects

• Data: opentransportdata.swiss – Federal Office of Transport (FOT/BAV)
• Protocol: Model Context Protocol – Anthropic / Linux Foundation
• Related: zurich-opendata-mcp – MCP server for Zurich city open data
• Portfolio: Swiss Public Data MCP Portfolio

Installation

Run via uv's uvx — no clone or manual install needed. Add to your MCP client config (mcpServers for Claude Desktop, Cursor and Windsurf; use a top-level servers key for VS Code in .vscode/mcp.json):

{
  "mcpServers": {
    "swiss-transport-mcp": {
      "command": "uvx",
      "args": [
        "swiss-transport-mcp"
      ]
    }
  }
}