The digital scheme will launch on East Midlands Railway between Leicester, Derby and Nottingham from Monday, September 1. Further trials are planned for Yorkshire from the end of September. Under the scheme, passengers will be able to check in and out of rail journeys using an app on their phone. The app will track journeys using the global positioning system (GPS) and then passengers will be automatically charged at the end of the day. When passing through ticket barriers, passengers will have to scan a unique bar code which appears on the app. The new tech, which is already being tested in Switzerland, Denmark and Scotland, is designed to replace the need for paper tickets and mobile tickets which use a QR code. Up to 4,000 people will be able to take part in the trials by signing up on train operators' websites. Ministers hope the trial will help to save passengers both money and time while travelling on the rail network. Rail minister Lord Peter Hendy said: "The railway ticketing system is far too complicated and long overdue an upgrade to bring it into the 21st century. "Through these trials we're doing just that, and making buying tickets more convenient, more accessible and more flexible. "By putting passenger experience at the heart of our decision-making we're modernising fares and ticketing and making it simpler and easier for people to choose rail." Oli Cox, head of commercial strategy and business planning at East Midlands Railway, said "more than 500 people" had already registered an interest in taking part in the trial. From the end of September, the trial will be extended to Northern Rail services between Harrogate, Leeds, Sheffield, Doncaster and Barnsley.