The British Rail Class 321 alternating current (AC) electric multiple units (EMU) were built by BREL York in three batches from 1988 to 1991. The design was successful and led to the development of the similar Class 320 and Class 322 units for use by Strathclyde PTE and Stansted Express (now used by Northern Rail) respectively. The British Rail Mark 3 bodyshell design was also used for construction of the Class 456 direct current (DC) units.
Three sub-classes of unit were built. The first two were built for the Network SouthEast sector, whilst the final batch was built for services around Leeds. These trains have been modified by different rail companies who use them such as Greater Anglia. The modifications include new seats, paintwork, lighting and in carriage announcement boards.
The first batch of 66 EMU trains, built between 1988 and 1990 were classified under TOPS as Class 321/3. Units were numbered in the range 321301-366 and have a maximum speed of 100 mph (161 km/h). Each EMU consisted of four carriages; two outer driving trailers, one of which contained first class seating; an intermediate motor coach with standard class seating only, roof mounted Brecknell Willis High Speed pantograph and four Brush TM2141C traction motors (two per bogie); and an intermediate trailer with standard class seating. The technical description of the formation is DTCO+PMSO+TSO+DTSO. These units were delivered in two groups, with individual vehicles numbered as follows:
Units 321301-346 Units 321347-366
DTCO 78049-78094 78131-78150
PMSO 62975-63020 63105-63124
TSO 71880-71925 71991-72010
DTSO 77853-77898 78280-78299
These EMU trains were built for outer-suburban trains on the Great Eastern Main Line, primarily from London Liverpool Street to Southend Victoria, Ipswich, Southminster, Clacton, Colchester and Braintree. They replaced the ageing slam-door Class 305, Class 308 and Class 309 units on trains to Clacton and Southend-on-Sea, and worked services on the newly electrified routes to Ipswich and Harwich. They also displaced many Class 312 slam-door units to the London, Tilbury and Southend Railway. Some of the Class 309 “Clacton Express” units were retained until 1994, and 24 of the newer Class 312 units were retained long-term to work services to Walton-on-the-Naze and peak services to Clacton, Ipswich and Witham. Units carried the distinctive Network SouthEast livery from new. 321361 was named ‘Phoenix’ in March 2008 at Ilford depot after it was rebuilt at the disused Colchester shed to repair damage caused by an arson attack at Southend Victoria on 10 July 2007.
The second batch of 48 units, built between 1989–90, were classified as Class 321/4. Units were numbered in the range 321401-448 and again have a maximum speed of 100 mph (161 km/h). The formation of these units is identical to that of the first batch, each unit being formed DTCO+PMSO+TSO+DTSO. They were delivered in two groups, with individual vehicles numbered as follows
These units were built for outer-suburban services on the West Coast Main Line, from London Euston to Watford, Milton Keynes, Northampton, Rugby, Coventry and Birmingham New Street.
All Units were delivered in Network SouthEast blue, red and white livery. They displaced the recently cascaded Class 317 units dating from 1981 that had themselves only just been introduced to the route to replace Class 310 units.
In 1996, units 321418 and 321420 were involved in a head-on rush-hour collision at Watford South Junction. Two vehicles of each set were extensively damaged. The remaining, undamaged, vehicles were reformed into a ‘new’ 321418, whilst the damaged vehicles were scrapped. Replacement vehicles were constructed, using the same vehicle numbers, taking the unit number 321420.
The EMD GP7 is a four-axle (B-B) road switcher diesel-electric locomotive built by General Motors Electro-Motive Division and General Motors Diesel between October, 1949 and May 1954. Power was provided by an EMD 567B 16-cylinder engine which generated 1,500 horsepower (1,119 kW). The GP7 was offered both with and without control cabs, and those built without control cabs were called a GP7B. Five GP7B’s were built between March and April 1953. The GP7 was the first EMD road locomotive to use a hood unit design instead of a car-body design. This proved to be more efficient than the cab unit design as the hood unit cost less, had easier and cheaper maintenance, and had much better front and rear visibility for switching.
Of the 2,734 GP7’s built, 2,620 were for American railroads (including 5 GP7B units built for the Atchison, Topeka and Santa Fe Railway), 112 were built for Canadian railroads, and 2 were built for Mexican railroads.
This was the first model in EMD’s GP (General Purpose) series of locomotives. Concurrently, EMD offered a six-axle (C-C) SD (Special Duty) locomotive, the SD7.
ALCO, Fairbanks-Morse, and Baldwin had all introduced road switchers before EMD, whose first attempt at the road-switcher, the BL2 was unsuccessful in the market, selling only 58 units in the 14 months it was in production. Its replacement, the GP7, swapped the truss-framed stressed car body for an un-stressed body on a frame made from flat, formed and rolled structural steel members and steel forgings welded into a single structure (a “weldment”), a basic design which is still being employed today. Unfortunately, in heavy service, the GP7’s frame would bow and sag over time. This defect was corrected in later models. The GP7 proved very popular, and EMD was barely able to meet demand, even after opening a second assembly plant at Cleveland, Ohio. Later, locomotives in EMD’s GP-series came to be nicknamed ‘Geeps’. Many GP7s can still be found in service today, although most Class 1 roads stopped using these locomotives by the early 1980s.
The GP7, GP9 and GP18 locomotives share a similar car-body that evolved over time. Most GP7s had three sets of ventilation grills under the cab (where the GP9 only had one), and two pair of grills at the end of the long hood (where only the pair nearest the end was retained on the GP9). However, some late GP7s were built with car-bodies that were identical to early GP9s. Early GP7s had a solid skirt above the fuel tank, while late GP7s and early GP9s had access holes in the skirt (see photo of Illinois Terminal 1605, top left). Many railroads later removed most of the skirt to improve access and inspection.
Locomotives could be built with the engineer’s control stand installed for either the long hood, or the short hood designated as the front. Two control stands for either direction running was also an option, but one end would still be designated as the front for maintenance purposes. The GP7 was also available with or without dynamic brakes, and a steam generator installed in the short hood was also an option. In the latter case the 1,600 US gallons (6,100 l; 1,300 imp gal) fuel tank was divided, with half for diesel fuel, and half for boiler water. One option available for locomotives without dynamic brakes, was to remove the two 22.5 in × 102 in (571.5 mm × 2,590.8 mm) air reservoir tanks from under the frame, and replace them with four 12 in × 150.25 in (304.80 mm × 3,816.35 mm) tanks that were installed on the roof of the locomotive, above the prime mover. These “torpedo tubes” as they were nicknamed, enabled the fuel and water tanks to be increased to 1,100 US gallons (4,200 l; 920 imp gal) each, although some railroads opted for roof-mounted air tanks and 2,200 US gallons (8,300 l; 1,800 imp gal) fuel tanks on their freight ‘Geeps’.
There are five GP7s on A J Kristopan’s EMD Serial number page that reused previous serial numbers: B&O 6405, CRI&P 1308 (2nd), L&N 501 (2nd) and 502 (2nd), and SLSF 615 (2nd). These rebuilt units were rebuilt as new on new frames. Another rebuild by GMD is that CN 4824 was rebuilt as a GP7 with parts from an F3A in October 1958.