TrainSim — train simulation for ATO

Python simulation of a train on a circular route. Provides the plant model that ATO controls.

Forgejo	https://git.italiatts.online/rwsholdem/trainsim
Language	Python (FastAPI)
Role	Physics, REST API, live route map

What it does

1. Simulates 1-D motion on a loop track (configurable length).
2. Exposes a lean HTTP API (see spec/interface.md — same contract as ATO).
3. Serves a route map at / — nodes, edges, moving train dot.
4. Optional door commands are accepted and logged as signals (no real doors).

Repository layout

Path	Purpose
trainsim/	FastAPI app, physics engine, config loader
config/sim.default.json	Physics gains, tick rate, max speed
config/track.default.json	Node positions + edge lengths (loop)
spec/	Interface contract + JSON examples (mirrors ATO repo)
static/map.html	Browser map UI
tests/	pytest (physics + API)

Interface (summary)

See spec/interface.md.

Method	Path	Body
GET	/train/state	—
POST	/train/actuate	{ traction_pct, brake_pct }
POST	/sim/start	—
POST	/sim/stop	—
POST	/train/doors	{ "command": "open" | "close" } (signal only)

Build & test

pip install -r requirements.txt
pytest -q
docker build -t trainsim .

Run locally

uvicorn trainsim.app:create_app --factory --host 0.0.0.0 --port 8080

Open http://localhost:8080/ for the map.

Run with ATO

See ATO repo — ./run-e2e.sh in CodeView profiles/ato-lab builds both images in nested DinD and runs a 15 s cruise demo.

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Detailed simulation notes — to be expanded in a later README revision.