A Google Maps mash-up has gone online that visualises the approximate location of every single tube train on the London Tube network. This has become possible since TfL's move to install an open API allowing access to their vast pool of data. Through this the map calculates real time location of trains by accessing the data from departure information board. This is the same information passengers see on the platform. The very familiar 7 minutes, 3 minutes, 1 minute, due, writing in orange dot letters.
The API is currently still in beta and provided through the LondonDataStore.
This comes only a few days after the publishing of the API and it was developed by Matthew Somerville via mySociety. The source code for the mash-up is also available. It was developed in the context of the science hack day that took place over the past weekend.
This is great to look at, but like the information on the tube platform, we know from experience that the time displayed usually is just an approximation.
In an earlier post the beat of the london tube network was covered in a different visualisation type, using timeLapse.
Image by wired.co.uk / Screenshot of the live tube map
Thanks for the link to Duncan.