About
This is E17 Trains — a tiny web app for watching London Overground trains pass through Walthamstow, from a handful of toddler-friendly viewpoints around E17.
My toddler loves trains. East Avenue is the bridge we cross most days on our regular walk. I wanted to be able to glance at my phone and know whether a train is about to pass underneath us — in either direction — without fishing through TfL's generic departure boards. You can now watch trains from a couple of different spots around E17 — tap the line name at the top to switch between them.
How it works
Live arrival times come from the TfL Unified API (public, unauthenticated). Your browser talks to TfL directly — there is no server in between me and you.
On the Suffragette line (Queens Road viewpoint), freight movements are pulled alongside passenger trains from the Realtime Trains Pull API via a small Netlify Function that holds the API credentials. Freight data contains information provided by Realtime Trains and is used here for non-commercial hobbyist purposes.
The countdown is time-until-the-train-crosses-the-bridge, not time-until-the-train-reaches-Walthamstow-Central. Northbound trains cross the bridge ~90 seconds after leaving the platform; southbound trains cross ~20 seconds before arriving. These offsets are field-observed and hardcoded.
The small horizontal strip under each countdown estimates where that specific next train is along the branch right now. On the Suffragette line, freight trains are drawn as a different shape — a diesel locomotive pulling a container wagon, in muted brown. Tap the cartoon train for a little honk. The passenger train wears a different outfit depending on the time of year; freight does not.
Source
Open source. github.com/bselby/Walthamstow-Train-Tracker