❓ Frequently Asked Questions

Trackser Live is a real-time API that transforms raw TfL TrackerNet data into clean, structured, and accurate train tracking information. We apply advanced normalization, deduplication, and enhancement techniques to provide reliable real-time train positions across the London Underground network.

Trackser Live provides more detailed, normalized data compared to what you see in the TfL app. We:

• Remove duplicate and stale train records
• Normalize inconsistent station names and locations
• Provide detailed location tracking with track codes
• Include stall detection to identify delayed trains
• Track train formations (when sets are split or joined)
• Provide historical context and averages for each location

The TfL app prioritizes general user information, while Trackser focuses on raw, detailed tracking data.

Yes, but with caveats. TfL's TrackerNet API updates approximately every 30 seconds, and we process and cache this data. The age of our data is typically 0-30 seconds behind the latest TfL update. We include an as_of timestamp in every response so you know exactly when data was last updated.

Currently, Trackser Live is in a closed beta and API keys are issued on a per-project basis. If you have a legitimate use case and want to explore API access, please contact us at support@trackser.co.uk.

Rate limits vary by API key and use case. Contact us for details specific to your project. We design limits to be reasonable for typical usage patterns.

API responses are typically returned in 50-200ms depending on line complexity and current system load. Responses are cached on Cloudflare's edge network globally for optimal performance.

Currently, the API is available to select partners and projects. While we have no plans to open it publicly at this time, we remain open to new opportunities. If you're interested in integration for a legitimate project, reach out to discuss your requirements.

When TfL's data doesn't provide precise platform information, we use track codes to infer the likely location. Sometimes the data simply doesn't include enough detail, so we provide the best information available: "Between [Station A] and [Station B]".

A stalled train is one that's been at the same location longer than historical norms. We compare current duration against averages to identify potential delays or dwell time issues. Not all stalls are problems—some are expected (terminus, driver changes, etc.).

During maintenance and service, train sets are sometimes split (one 8-car train becomes two 4-car trains) or joined. We detect these events by tracking vehicle IDs and formation numbers, flagging them so you can understand changes in train data.

This comes directly from TfL's data and is typically accurate to within a minute. However, it can vary based on service conditions, delays, and the age of the prediction. Use it as a guide, not a guarantee.

If TrackerNet (our primary source) becomes unavailable, we can fall back to the Unified API which covers the same lines with slightly less detail. If both sources fail, we continue serving cached data until service is restored. We'll post status updates on the System Status page.

These are two different TfL data sources. TrackerNet is the legacy system with detailed Underground data; Unified is the modern system covering all TfL services. We use both strategically—TrackerNet for its detail, Unified for its breadth. Learn more on our Data Sources page.

Trackser Live currently focuses on the core Underground network. Other TfL services (Elizabeth line, DLR, Overground) have different data structures and would require additional implementation. As demand grows, we may expand coverage.

We'd love to hear from you! Please email support@trackser.co.uk with details about the issue or your suggestion. Include the timestamp and line/train details if reporting a data accuracy issue.

Reach out to us at support@trackser.co.uk and we'll get back to you promptly. We're always happy to discuss use cases and answer technical questions.