The 143 series and 145 series are types of electric multiple unit for non-passenger trains developed by Japanese National Railways. They are different series but their purposes and appearances are very similar. Today, they are used as shunters and "alternative cab units", used when intermediate carriages run between depots. There were also parcel and mail trains in the past.
The 143 series was based on 141 series mail train (in service: 1967-86). JNR introduced the 143 series built from the ground up to replace older shunters, mail and parcel trains, which were incompatible with new signalling systems. There were four types in total: KuMoYa 143 (shunter and alternative cab unit), KuMoNi 143 (parcel train), KuMoYu 143 (mail train) and KuMoYuNi 143 (mixture of both mail and parcel train). JR East took over all KuMoYa 143s and a few KuMoYuNi 143s when JNR was privatised in 1987.
Until the 2000s, JNR and JR East managed EMUs in a way different from today. For example, a 10-car commuter train was divided into pairs of several carriages when a major overhaul was taken place. When intermediate carriages were sent from a depot to another one, they could not run without a locomotive or alternative cab unit like the KuMoYa 143. In addition, KuMoYa 143s were used for a few passenger trains (mostly rail tours) when an old train incompatible with modern signalling systems ran. After 2000s, the KuMoYa 143s became redundant as they were not compatible with newer trains introduced by JR East. Furthermore, major overhaul of a few old trains is now carried out without dividing a trainset, meaning that intermediate carriages no longer run mainlines solely. Since then, JR East used them mostly for transporting staffs between a depot and a nearby station, but they dramatically declined in the late-2000s and 2010s. All of them have been deregistered for mainline use by 2022.
KuMoNi 143 (parcel), KuMoYu 143 (mail) and KuMoYuNi 143 (mail & parcel) usually joined to other trains such as 113 series. All but two were withdrawn by 1986 when mail and parcel trains were discontinued. Two carriages of KuMoNi 143 were converted to KuMoYa 143, and KuMoYu 143 carriages were converted to 123 series for passenger trains. However, the other KuMoYu 143s have never been reinstated despite they were just four years old, as KuMoYu 143s were owned by Ministry of Posts and Telecommunications, not Japanese National Railways.
The 145 series is similar to the 143 series, but the 145s were rebuilt from 101 series commuter trains (in service: 1957-2003). There were KuMoru 145 & KuRu144 (wagon unit), KuMoYa 145 (shunter and alternative cab unit) and KuMoYuNi 147 (mail & parcel train).
KuMoRu145 and KuRu 144 together formed a two-carriage unit. It was designed for carrying bogies, air-conditioning and other equipment for trains between depots. Its front end looked like 103 series, but behind the driver's room was a cargo bed. When JNR was privatised in 1987, JR East and JR West took them over. They became redundant in the 1990s as both JRs started using lorries instead of the wagon units to transport heavy equipment. Most KuMoRu 145 and KuRu 144 units were scrapped by the 2000s, and the last one was deregistered in 2021.
KuMoYa 145 was designed as a shunter and alternative cab unit, just like KuMoYa 143 mentioned above. JR East, JR Central and JR West inherited them following the privatisation of JNR. Those owned by JR Central were withdrawn by 2008, and those of JR East by 2020.
KuMoYuNi 147 was a type of mail and parcel train. Unlike KuMoYuNi 143, the KuMoYuNi 147 was designed for Iida Line, where many steep gradients and tight curves exist. They were taken out of service in 1986 when mail and parcel trains were all discontinued.
Some KuMoYa 145 and all KuMoYuNi 147 were converted to 123 series.
Current Operations & Future Prospects
JR West has KuMoYa 145 carriages and uses them as shunters. They seldom run mainlines as alternative cab unit (empty coaching stock movement). They are also likely to be withdrawn in the near future, but presumably after retirement of other old trains (e.g. 115 series).
