Between 1910 and 1985 the South End Signal Box at Paekakariki Railway Station was the main control centre for trains travelling through Paekakariki on the Manawatu Railway line. It is now a relatively rare, remaining example of the once common signal box.

The Manawatu Railway line was built and operated by the Wellington & Manawatu Railway Company and was extended as far as Paekakariki in 1886. In 1908 the Government purchased the line from the company and the Railways Department embarked on an extensive programme to upgrade facilities at Paekakariki Station. As well as constructing two signal boxes and several new buildings, the Department spent £2,500 on installing the newly developed 'electric train tablet signalling system'. Controlled by the signal boxes, the electric train tablet signalling system was designed to prevent crashes by ensuring that trains travelling in and out of the station maintained a safe distance from each other.

Signal boxes were constructed to a standard design throughout the country and the South End Signal Box is a typical example. The South End Signal Box was a two storey, timber building. It was 8 metres high and consisted of two small rooms which measured 3.4 metres by 4.9 metres. Access to the upper storey was via an external, dogleg staircase and it featured large, continuous windows that gave the signalman an excellent view of the railway line. From the South End Signal Box all train movements on the main-line were monitored and controlled with the aid of a 24-lever operating system that was linked to the North End Signal Box, and the station signals and points. To prevent accidents, an interlocking system on the ground floor ensured that the signalman could not mistakenly send signals that would allow two trains to proceed along a piece of track in opposing directions at the same time.

The signal boxes and signalling system came into use on 31 January 1910. Upgraded a number of times, the South End Signal Box remained in use until 1985, when the 'Central Traffic Control System' (CTC) finally reached Paekakariki. First used in the early 1940s, CTC allowed all signals along a railway line to be remotely controlled from the Train Control office in Wellington, effectively removing signalling responsibilities from individual railway stations. Made redundant by CTC, Paekakariki's North End Signal Box was removed, and is now part of the historic Ohakune Railway Station complex. The South End Signal Box, owned by the Paekakariki Station Precinct Trust was relocated to railway land north of the station and then across the rail tracks adjacent to the station car park. It has been fully restored by local community efforts and returned to the south end of the station platform to its original siting in December 2007. It was re-opened on 6 August 2008, coinciding with the centennial of the North Island Main Trunk Line when a Parliamentary Special Steam Train stopped at Paekakariki Station for the unveiling.

The South End Signal Box has national significance as a rare, remaining example of the signal boxes that controlled train movements throughout New Zealand in the early twentieth-century. One of the few still located near its original site, the Signal Box is part of an important railway complex that adds significant insight into its traditional function and increases its educational potential. The Signal Box has historical significance for its association with the development of the North Island Main Trunk Line and technological advances on the New Zealand railway. The Signal Box is also of considerable physical interest as it is in close to its original form and still contains the levers and interlocking system that controlled the station signals and points.