Since 1999, Sentinel has been the chosen identity card scheme for making sure that people who work on or near Network Rail’s infrastructure have basic competence and are medically fit to do so.

The system, owned and developed by Network Rail, is based on a central database and a common system for checking that people hold a core competence, a medical certificate and a drugs & alcohol (D&A) certificate.

Originally a paper-based approach was taken and the system – though better – was not perfect.  Re-printing of cards was necessary if something changed and there was no capability to easily verify or authenticate the information being presented.

2013 saw a significant upgrade to the Sentinel system, making use of electronic chip technology within newly formatted cards.  This allows near real time checking of competence using a variety of authentication methods such as smartphones, PC access or simple scanning of a QR code on the cards.  It is now possible to check the card against the central database in near real time using internet connectivity.

In 2014, Transport for London (TfL) became the first other Rail Entity to adopt the system.

With further enhancement projects in 2016, the Sentinel system is now being used to control site access and improve the management of fatigue risk.

Since 2016 updates have been made to the system, with user experience at the forefront.

In 2021 Network Rail (High Speed) became the second Rail Entity to onboard on to the system enabling them to validate Authority to Work (ATW) on their infrastructure.

2023 was a big year with the introduction of virtual Sentinel cards that could be accessed via a smartphone as well as an interface makeover.

To enhance security, Two-Factor authentication was introduced in 2024 for Sentinel administrator users.