Porterbrook

Porterbrook was established on 21 March 1994 as a subsidiary of British Rail in preparation for the privatisation of British Rail. It was named after the Porter Brook, a river that passed by British Rail's Sheffield offices (Specifically Sheaf House, adjacent to Sheffield railway station, which was demolished in late 2005 as part of a city centre regeneration project). In November 1995, Porterbrook was privatised via a management buyout.

In 1996, Porterbrook entered the freight leasing market though a deal to purchase and lease back 70 locomotives and 699 wagons from Freightliner. On 28 August 1996, the company was purchased by the transport conglomerate Stagecoach in exchange for £825 million; this deal was subject to considerable criticism for the low value returned to the taxpayer. On 20 April 2000, Stagecoach opted to sell Porterbrook to the British banking group Abbey National for a reported £1.44 billion.

Porterbrook established its own subsidiary to handle its European rail leasing activities; this was sold to a joint venture between Babcock & Brown and Bank of Scotland Corporate Europe during December 2004, creating CB Rail. At the time of the takeover, the subsidiary had leasing arrangements for 28 locomotives and 67 coaches.

On 27 October 2008, the business was purchased from Abbey National by a consortium of Antin Infrastructure Partners, Deutsche Bank and Lloyds TSB. The sale, which reportedly valued Porterbrook and its 6,014-strong rolling stock inventory at £2 billion, gave rise to concerns that Abbey National, and its Spanish parent Banco Santander, were subject to considerable financial stress at that time.

During the 2010s, Porterbrook engaged in various efforts to overhaul and refurbish elements of its rolling stock, particularly multiple units. One proposal was the refurbishment of its British Rail Class 144 'Pacer' diesel multiple units, referred to as the Class 144e (Evolution), it would bring it up to the requirements of the Persons with reduced mobility-Technical Specifications for Interoperability accessibility regulations. It featured several upgrades such as the addition of new 2+2 style seating, a fully accessible toilet, two wheelchair spaces and spaces for bicycles and luggage, as well as Wi-Fi and media screens.

In December 2016, Arriva UK Trains subsidiary Northern and Porterbrook announced a plan to convert eight Class 319 electric multiple units to bi-mode units, to allow through working between electrified and non-electrified routes. These units, which were initially marketed as "Class 319 Flex", have been designated as Class 769 under TOPS, will use newly installed diesel engines and alternators fitted under each of the driving trailer vehicles, to power the traction motors through the train's existing DC bus.

During the 2010s, Porterbrook begun disposing of their Class 43 power cars, used on Intercity 125 services; a number of power cars (along with a set of Mark 3 coaches) were acquired by Locomotive Services Limited, while the two locomotives involved in the record breaking test run were donated, one, 43102, to the national collection at Shildon, and the other, 43159, to the 125 Group.

During 2019, Freightliner purchased 13 Class 90 electric locomotives from Porterbrook that were formerly operated by Greater Anglia. Upon their transfer in May 2020, they underwent a modification programme to match the freight Class 90 specification. In February 2020, Porterbrook signed a 15-year lease with St Modwen to take over the Quinton Rail Technology Centre at Long Marston.