British Rail Class 323

In the early 1990s the Regional Railways sector of British Rail placed an order for new EMUs both to replace older electric units around Birmingham and Manchester, and to work services on the newly electrified Birmingham Cross-City Line. In June 1990, the contract was awarded to Hunslet Transportation Projects of Birmingham, a new company set up by a team of engineers and managers who had left Metro Cammell. Metro Cammell was at the time a Birmingham-based train builder. It won the contract in competition with six other European train builders. The trains were designed in Birmingham, but built and fitted out at the Hunslet works in Leeds.[8]

Initially 37 units were ordered, with the option for fourteen more. Eighteen would be needed for the Cross-City Line, while the remainder would replace older units (such as the Class 304 and Class 310) in the event a total of 43 three-car units were actually built.[8] When the electrification of the Leeds/Bradford - Skipton/Ilkley Airedale/Wharfedale Lines was confirmed in the early 1990s, Regional Railways and West Yorkshire PTE applied to the government for 14 units to add to those already on order.[9] At the time, government spending on the railways was restricted due to the looming privatisation and eventually, when funding was not forthcoming, the order was cancelled, and 21 second-hand 308s from Network SouthEast were used in the interim before the Class 333s were delivered in 2001.[10]

The units are known for a distinctive whine made during acceleration or deceleration, rising/falling through multiple phases falsely suggestive of a motor connected to a gearbox with a great many ratios, caused by use of a gate turn-off thyristor-based inverter as part of the traction control circuitry that drives the 3-phase AC motors, a common setup in the early to mid 1990s which is notably also present in the Networker family of electric multiple units. The "gear-changing" effect is produced by the simplification of the PWM pulse pattern so as not to overload the thyristor, which switches at lower frequencies than later implementations of the variable-frequency drive and hence produces a lower-pitched sound.[11]

The 323s were expected to leave Northern in December 2018 when replaced by the Class 331;[19][20][21] however, this did not take effect.

The Northern Trains 323 fleet will be retained, replacing the older Class 319s, and being joined by 17 units cascaded from West Midlands Trains.[22]

Class 323s operated by both Northern Trains and West Midlands Trains received a full refurbishment between 2018 and 2021, with the first refurbished units delivered to West Midlands Trains in February 2019,[23] and the first Northern unit (323234) returning on 22 October 2019. The rest of fleet was refurbished to the same standard over the following years.[24]

These works involved the replacement of seat covers, interior and exterior repainting (into the new livery of their respective operators), the installation of a new passenger information system and wheelchair call-for-aid buttons, and the addition of an accessible toilet in place of the original small toilet cubicles, among other modifications.[25] The last Class 323 unit to be refurbished (323224) returned to Northern Trains on 23 January 2021, while the last West Midlands Trains 323 unit (323226) was returned in 2020.[26]

Many of these changes are a requirement of the PRM (Persons with Restricted Mobility) TSI, with which all UK trains must be compliant to continue running beyond the end of 2019.[27]

Named units are as follows:

323241 “Dave Pomroy 323 Fleet Engineer 40 years service” This unit also carries a sticker celebrating the Cross City line electrification with the words “Soho LMD 1993 Cross City line“[28]

Class 323241 with Dave Pomroy 323 Fleet Enginer 40 years service and Soho TMD 1993 Cross city line stickers