- British Rail Class 311
Infobox EMU
name = British Rail Class 311
imagesize = 265px
caption = Unit 311104 in blue/grey livery awaiting passengers at Partick.
background = #012545
Manufacturer = Cravens
Formation = 3 cars per trainset
Built = 19
InService = 1967 - 1999
Weight = Total - 129 tons
Capacity = 236 seats
MaxSpeed = 75mph (121km/h)
Gauge = RailGauge|sg
Brakes = Air (Auto/EP)
Engine =
Operator =British Rail TheBritish Rail Class 311alternating current (AC)electric multiple unit s (EMU) were built byCravens atSheffield in1967 . They were intended for use on the line from Glasgow Central to Gourock and Wemyss Bay, which was electrified in 1967.Appearance
Outwardly, the units were virtually identical to the earlier Class 303 units built in
1960 . The interiors were also very similar, although the Class 311s had fluorescent lighting (unlike the Class 303s which were fitted with tungsten filament bulbs).Along with the Class 303s, the wrap-around driving cab windows were replaced with flat, toughened glass in the 1970s to give better protection to drivers in the event of attacks by stone-throwing vandals.
Construction
19 units were built, initially classified as AM11 units, and numbered 092-110. This was later changed to Class 311 under the
TOPS system, and the units were renumbered 311092-110. Each unit was formed of three carriages; two outer driving trailers, an intermediate motor coach. The technical description of the formation was BDTCOL+MBSO+DTSO. Individual carriages were numbered as follows:
*76403-76421 - BDTCOL
*62163-62181 - MBSO
*76422-76440 - DTSOOperations
The units were built to operate services on the newly electrified routes from Glasgow Central to Gourock and to Wemyss Bay; now known as the Gourock and Wemyss Bay branches of the
Inverclyde Line .In practice, the Class 311s operated almost interchangably with the Class 303s. The units could be found in service across the Glasgow electrified suburban network (north and south of the Clyde, and as far south as Ayr).
Consideration was given to upgrading 11 of the units for the Ayr line electrification until it was found to be cheaper to buy 20 of the new Class 318 and the plan was cancelled.
Withdrawal
Being a much smaller fleet, the Class 311s were replaced (in the 1990s) earlier than the Class 303s.
After being withdrawn from normal traffic, two units, nos. 311103/104 were transferred to departmental duties as Class 936 sandite units, nos. 936103/104. These lasted in service until
1999 , when they were withdrawn. They were not scrapped immediately asRailtrack was anxious to ensure that one of the units was preserved. In2002 , it donated one of the units to theSummerlee Heritage Park museum inCoatbridge . The other unit was scrapped in2003 .Preservation
*311103 - 76414+62174+76433 -
Summerlee Heritage Park ,Coatbridge (One driver trailer since scrapped)This unit was the former Class 936 sandite unit, no. 936103, formed of 977844+977845+977846.External links
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