The proposed Paeroa-Pokeno railway line or deviation in the North Island of New Zealand between Paeroa and Pokeno was a favourite scheme in the 1920s and 1930s. When work started in 1938, it was said that the proposed 47 km (29 mi) line, which had been surveyed 18 years earlier, would shorten the distance from Auckland to towns on the ECMT by nearly 80 km (50 mi). But it "never quite got off the ground", although some 13 km of formation was carried out from 1938 after Bob Semple turned the first sod on 27 January. Work was still making slow progress in 1950, when a paragraph in the Ministry of Works annual report said 20 private crossings had been formed and metalled and 456 ft (139 m) of culverts installed. Very little is now visible.
The Kaimai Tunnel relegated this section to ghost status; in August 1962 a deviation from Wahora to Apata passing under the Kaimai Range in a long (8.85 km) tunnel was approved . Work on the tunnel did not commence until 1969. With the opening of the tunnel in 1978, the Paeroa - Katikati section of the East Coast Main Trunk was closed
Originally the line was to be the first part of the East Coast Main Trunk Railway crossing the Bay of Plenty to Opotiki and then inland to Gisborne via the Moutohora Branch.
In 2014 the New Zealand First political party included a proposal to investigate a Pokeno-Paeroa-Te Aroha-Kaimai tunnel line as part of its transport policy. The proposal consists of completing the uncompleted Pokeno-Paeroa line, re-using part of the former Thames Branch between Paeroa and Te Aroha and a new link between Te Aroha and the western portal of the Kaimai tunnel, altogether creating a more direct link along a faster route, providing more capacity on the very busy rail freight corridor between Auckland and Tauranga, together with linking the towns of Maramarua, Ngatea, Paeroa and Te Aroha as potential future satellite suburbs of Auckland on a new commuter rail service route between Auckland and Tauranga.