British Rail Class 306

Infobox EMU
name = British Rail Class 306

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imagesize = 300px
caption = The preserved Class 306 train (unit 017) as seen on the launch day of Network SouthEast. This view also shows the carriage which was not modified when the trains were converted from the dc to ac power supply system.
background = #012545
Manufacturer = Eastleigh Works
Formation = 3 cars per trainset
Built = 92 trainsets
InService = 1949 - 1980
Weight = Total - 105 tons
Capacity =
MaxSpeed = 75mph (121km/h)
Gauge =
Brakes =
Engine =
Operator = British Rail

The British Rail Class 306 was a type of electric multiple unit (EMU) introduced in 1949. It consisted of 92 three-car trains which were used on newly electrified suburban lines between Shenfield and London Liverpool Street.

Overview

Class 306 trains were built to a pre-World War Two LNER design by Metro Cammell and Birmingham RCW, and were equipped with English Electric traction equipment. Each carriage featured two sets of twin sliding passenger doors, which could be opened by either the guard or the passengers using the passenger operated buttons fitted next to them, on both the outside and inside of the trains.

When first built the trains were energised at 1,500 V direct current (DC) which was sourced from overhead wires, being collected by a cross-arm pantograph located above the cab on the Motor Brake Second Open (MBSO) vehicle.

In the early 1960s the overhead wires were re-energised at 25,000 V alternating current (AC) (and 6,250V AC in the London area) and the trains were rebuilt to operate using this very different electrical system. This entailed the fitting of a transformer and rectifier unit, which were located on the underframe between the bogies of the intermediate carriage. At the same time the location of the pantograph was moved to this carriage as well. Because this reduced the headroom inside the train, the guards' compartment was relocated to be directly below the pantograph, which was replaced with a more modern single-arm design. The trains were then re-numbered 001-092 with the last two digits of each carriage number (previously numbered in the LNER coaching series) the same as the unit number.

Withdrawal and preservation

The Class 306 trains were withdrawn in the early 1980s, and one unit, 306017, has been preserved. It has been repainted in a near original green livery, albeit with a yellow warning pannel on the front to comply with present-day safety regulations. It has recently been transferred to the Shildon Locomotion Museum.

See also

*Class 506 EMUs - similar to the Class 306 EMUs, but built for the Manchester-Sheffield-Wath electric railway

External links

* [http://www.therailwaycentre.com/index.html The Railway Centre]