Services are currently operated by dual-voltage Class 717 electric multiple units (EMUs), which replaced Class 313 units as part of a franchise commitment when Govia Thameslink Railway took over management of the line and its services. The Class 717s began to enter service in March 2019. To comply with the health and safety regulations for trains operating in single-bore tunnels where there is not enough clearance space for side evacuation, they have emergency doors at both ends of a unit. When operating on , the two motor coaches of a Class 313 collected traction current from their own shoe gear only; there was no traction bus linking them together as found on most Electric Multiple Units. All of the Class 313 units when operating on the NCL had their Driving Motor B vehicle at the London end, and whilst on were electronically limited to , which is the maximum line speed. All stations are long enough to accept six-car trains.