# Tube Heartbeat — a week of London

> A week of the network's own rhythm, hour by hour, across the forty busiest interchanges.

- Category: Transport
- Cadence: live
- Status: Live: values change continuously; cite the retrieval time.
- Dataset key: `tube-heartbeat`
- Source: [TfL Unified API](https://api.tfl.gov.uk/)
- Licence: TfL Open Data Licence — [terms](https://tfl.gov.uk/corporate/terms-and-conditions/transport-data-service)
- Canonical page: [https://londongraph.com/g/tube-heartbeat](https://londongraph.com/g/tube-heartbeat)
- Machine-readable record: [https://londongraph.com/data/tube-heartbeat](https://londongraph.com/data/tube-heartbeat)

## Methodology

TfL's published crowding profile for the forty busiest interchanges — seven days of fifteen-minute bands, averaged to the hour and across stations. The figure is percentage of each station's own baseline, not passengers: a busy quarter-hour at Brixton and at Bank both read high without either claiming to be the busier station, which makes the shape of a day comparable between stations and the height meaningless between them. Earlier versions of this page said the data did not exist; it does, and this is it.

## Visualisations

- [Heatmap](https://londongraph.com/g/tube-heartbeat): A week of the network's own rhythm, hour by hour, across the forty busiest interchanges.
- [Profiles](https://londongraph.com/g/tube-heartbeat?view=profiles): Read each row as an aligned trend rather than a colour cell.
- [Distribution](https://londongraph.com/g/tube-heartbeat?view=distribution): Rank the values in the selected matrix.

## Citation guidance

Attribute the original publisher named above and identify LondonGraph as the visualisation and methodology layer. Do not describe live values as a historical census, and do not present placeholder values as observations.