The Class 144 Pacer units were constructed by BREL between 1986 and 1987 in Derby with bodywork produced by Walter Alexander of Falkirk, who had similarly bodied the Class 143s. The Pacer family (142-144) were aimed at replacing much of the remaining 1st Generation units that were still in use, many of which required extensive, costly work if they were to remain in traffic.

Used extensively in the North of England, particularly Lancashire and Yorkshire, the Pacers earned their keep on local services as intended. The fixed axle design wasn't always associated with comfort, but with over 30 years in service they certainly filled a gap. During their early life the class was upgraded to include Cummins engines and Voith transmission to improve reliability as well as internal refits along the way.

The class were due for withdrawal towards the end of 2019 although some remained until 2020, The withdrawal was primarily due new accessibility and disability requirements for the National Rail Network. Some of the now 30+ year old sets were also approaching life-expiry.

Whilst it could be argued that 2nd generation units divide opinion somewhat in terms of preservation, they are a part of the British Rail story and certainly have a following. The 2G classes have been found to be very suitable for use on presereved railways and over a dozen 144s have been secured for future use around the country.

144009 arrived in Bury during September 2020 for storage on behalf of Greater Manchester Fire and Rescue Service who had secured the set for their training facility in Bury. The unit was resurrected and found to be in generally good working order, so with the blessing of the Fire Service it was used for some passenger work and undertook a number of filming assignments, including starring in the BBC Series 'Sherwood', where it gained the fictional Great Midlands Trains livery, applied using vinyl wraps.

In early 2022 144009's long term prospects changed with a private owner taking over the unit in an agreement with the Fire Service where another, less serviceable classmate, 144010 would be provided in exchange. This change of plan also meaning that 144010 can be used a source of spares and equipment for 009, the Fire Service not requiring a fully working example for their needs.

Work has progressed to keep 009 in working order and a number of further improvements are planned. The 144 now joins the DMU fleet and will be seen in service at the ELR alongside 1st Generation DMUs and will help in reducing some of the burden on the older 1G units, allowing further restoration and improvements to be undertaken on them.