One common type of Great Northern Railway signal consisted of a somersault lower quadrant arm on a lattice post, with a ball and spike finial and round-case lamp. Post-Grouping, the LNER modernised many of these signals by replacing the arm with the upper quadrant Westinghouse type. A square-case lamp was also fitted at the same time. The resulting design was also used for new installations. An alternative finial is supplied to represent the shallow pyramidal pattern used on later LNER signals. Some examples are still in use on Network Rail today.