Signalling on the single-track sections (most of the line) was controlled by Tyer's Electric Train Tablet No 7 system; with each of the stations for the 94 tablet sections staffed by three tablet porters each working a 56-hour week for continuous coverage; hence each station required at least four houses for the stationmaster and three porters. Pierre noticed that with CTC station buildings and even platforms had been removed as there were no longer any staffed stations between Ohakune and National Park. The Train Control system introduced from 1928 to 1932 supplemented the tablet system by operators at the four sections (Auckland, Frankton, Te Kuiti, Ohakune, Marton and Wellington) to expedite operation of trains over several tablet sections; the 1925 Fay-Raven report urged its adoption because of the "fitful progress" of mixed trains, with locomotives often kept waiting. From 1938 to 1966 Centralised Traffic Control (C.T.C) gradually replaced the Tablet system on the NIMT. In 1957 when the installation of CTC over the remaining 354 km commenced, it was estimated that using CTC over the 330 km Taumarunui to Otaki section with control centres at Ohakune (shifted to Taumarunui in 1977), Taihape and Palmerston North would replace 74 men in traffic working duties. The last section converted was Piriaka-Owhango.