couplers and lacing side buffers. Service history Prior to the commencement of electric services between Crewe and Manchester, the AM4 underwent a period if testing on the Styal line. Somewhat unusually, the AM4s were the only AC units of the 1959 design to wear the lined-out version of Multiple Unit Green livery, with Classes 305 and 308 emerging in comparatively drab plain green. This pleasant appearance was lost, however, when repainted into all-over Rail Blue. AM4s of the second batch unit numbers 016 to 023 were loaned to the Eastern Region for use between Liverpool Street to Shenfield, Southend Victoria and Chelmsford after the conversion of the route from 1,500 V DC to 6.25 kV/25 kV (ac) while Class 306 and Class 307 units were being rebuilt to 6.25kV/25kV ac. Some of the second batch were also briefly used on the services from Liverpool Street to Hertford East and Bishops Stortford in the mid-1960s. The AM4 units largely spent their whole careers operating between Crewe and Altrincham via Stockport, or Styal and Manchester, Crewe and Liverpool, Crewe and Birmingham, and Birmingham - Rugby - Northampton. Individual units were occasionally operated to London Euston (notably at the very beginning of electric services, before all the AM10 units were delivered) or Preston, but on rare occasions. Because of their operation on much of the West Coast main line, the units attained substantial mileage at their 75 mph maximum speed each day on their workings, unlike those employed on suburban services elsewhere. Refurbishment Between 1984-86 a refurbishment programme was carried out on the units. This included the removal and scrapping of the Trailer Composite vehicles, reducing the units to three-car formation, and the conversion of the Motor Brake vehicles of the first batch (Class 304/1) to saloon layout, reducing seating capacity to 72. Unlike other EMU refurbishment programmes, the work carried out on Class 304 units did not include the fitting of inter-vehicle gangways, or the complete replacement of internal fittings. This meant that original 1960s seats and trim remained in most vehicles, retaining something of their original character. The units were also repainted into blue and grey livery. The loss of one vehicle meant that the power-to-weight ratio of the units increased, thereby improving their performance. Decline During the 1980s, the units gradually received the Class '304' TOPS prefix to their unit numbers, and by 1992, several later series units had even