While trains only operated as far north as Upper Hutt, they were not protected by fixed signals. It was felt that as services were few, slow, and operated only in daylight hours, signals were not necessary. Upper Hutt was one of the first stations on the Wairarapa Line to receive signals, with initial instructions requiring south-bound trains to wait in the siding or loop, and north-bound trains to take the main line. These signals were first listed in the working timetables of 1887. By 1921, increased traffic was causing operational issues, and it was decided to install new automatic signalling which had been recently developed in the United States. Work began in 1921, and by early 1923 was operating between Wellington and Upper Hutt.