union ASLEF, ScotRail's Class 153s can only be driven from the A-end cab the B-end cab being considered too cramped for long-distance driving. The first unit began service on 19 July 2021. Network Rail In May 2021, Network Rail purchased three for use on infrastructure monitoring services. Former operations Regional Railways Regional Railways operated Class 153s on many branch lines throughout the Midlands, Wales and Northern England, both individually and with other classes of Sprinter unit. They were initially allocated to Heaton (15), Cardiff Canton (9), Plymouth Laira (10), Crown Point (16) and Tyseley (20). Class 153s were often found working services from; to to to via Leicester to to and to and Post privatisation In the lead up to privatisation of British Rail, ownership of the fleet passed to Angel Trains (30) and Porterbrook (40) in April 1994. Upon privatisation, they were initially operated by Anglia Railways, Central Trains, First North Western, North Spirit, and Wales & West. South West England First Great Western took over the Wessex Trains fleet upon the merger of the two franchises. Wessex Trains had, in turn, inherited its fleet of 13 units from its predecessor Wales & West. Units were used on local services in Cornwall, Devon, and around Bristol. They were also used on Bristol Temple Meads to Weymouth, Southampton Central, and Worcester Foregate Street services, and the Swindon via Melksham to Southampton Central service. In mid-2004, Wessex Trains received a further two units from Central Trains to allow it to lengthen some services. Following the introduction of a new timetable in December 2006, four units were taken off lease and stored at Eastleigh Works. After a period in storage these four units were pressed into service with East Midlands Trains. In December 2007, First Great Western received an additional Class 153 from Arriva Trains Wales, bringing its total to 12. This unit arrived in the blue with gold star livery of former operator First North Western. For summer 2011, two London Midland Class 153s were allocated to the South West for strengthening purposes, based at Exeter TMD for the duration. This allocation was eventually made permanent as a result of London Midland keeping three Class 150 units after the new Class 172s entered service. This brought First Great Western's number of Class 153 units up to 14. Nine of those 14 units later left the fleet, with the remaining five moving