Anyone understand Gps tracks* re trains?

This is something I have an interest in. Real time trains are currently requesting help with Gps tracks. There is no method of contact on the site to find out a bit more info of how it works.

Anyone familiar with this stuff at all? I like techy stuff and am interested.

From the site: (The email in the description below is an auto response type only).

How you can help us

We are opening a call for any and all GPS tracks of train services. If you have a smartphone, then there are apps available that will let you log a track and then export it in a GPX format, there are a wide range of options on each app store. Once you have a track exported in GPX format, please email it to tracks@realtimetrains.co.uk with a link to the service from Realtime Trains.*Please try and send only one service per track.

http://www.realtimetrains.co.uk/tracks/

Presumably they mean use something like this on your phone when you're on a train journey, save the log as a GPX file, and email it to them.

------------error post