Train drivers’ outside attention impacts the chance of acting in time to avoid potential collisions with people or other objects. This project aimed to study the effect of the in-cabin signalling system ETCS on driver attention. We specifically examined gaze behaviour in events of special relevance for train driving, such as unattended level-crossings, with and without speed changes. An eye-tracking study was conducted in a simulated environment with 40 experienced Swedish train drivers driving the same route equipped with the Swedish lineside signalling system ATC and ETCS, respectively. The results showed that ETCS generally affected drivers’ outside attention negatively. Compared to ATC, with ETCS significantly more glances were directed inside the cabin at the expense of outside glances. When assessing the gaze behaviour at unattended level-crossings with and without speed changes, approximately 20 percent less attention was spent towards the outside when approaching an unattended level-crossing with a speed change. We conclude that ETCS negatively affects outward attention and thus reduces the chances that the driver will detect a person or other object on the track and act in time to avoid a collision. As speed changes negatively affect outward attention, we recommend that speed changes should be avoided in critical parts of the track where the risk of collision is higher. The results should also have implications for the design of connected driver advisory systems, which provides the driver with real-time guidance on speed operation via a tablet or screen and thus, demand driver attention.