Automatic notching was provided. When the trains were running in the Mersey Tunnel where there is a gradient of 1 in 27, provision was made to increase the notching point of the acceleration relay. This could be actuated by a sealed push-button in the driver's cab, for use in exceptional circumstances, such as a six-car train operating with one motor coach out of action. Tuplin wrote that the new vehicles did not have an on-board air compressor; at the end of the run: