NEWAG, the manufacturer of the Impuls family of trains, put code in the train's control systems that prevented them from running if a GPS tracker detected that it spent a certain number of days in an independent repair company's maintenance centre, and prevented it from running if certain components had been replaced without a manufacturer-approved serial number.

The manufacturer wants the repaired trains immediately removed from service because they have been "hacked" and might be unsafe, although it has not come up with any proof that this is the case.

The situation is a heavy machinery example of something that happens across most electronics categories, from phones, laptops, health devices, and wearables to tractors and trains.

This anti-repair mechanism is called "parts pairing" and is a common frustration for farmers who want to repair their John Deere tractors without authorisation from the company. Apple also uses it to prevent independent repair of iPhones.