They were very similar in appearance to Class 26 locos, but carried Southern Region two-digit headcode blinds between the cab windows.

On secondary and branch lines not electrified, such as Tonbridge – West St. Leonards, diesel electric multiple units would work passenger services.

Phase 1 would cover the north Kent routes via Chatham and Margate,[7] including the Sheerness line, which had not featured in any previous electrification proposals.

The Electrification Committee informed the BTC of their requirements in October, advising them that they had been in contact with Sulzer Brothers Ltd. to determine whether or not a locomotive in the 1,500 to 1,750 horsepower (1,120 to 1,300 kW) range could be built.

[8] A few days later, BTC Chairman Sir Brian Robertson told a director of Vickers-Armstrong Ltd. of the plan at a social event.

They were to be built by the Birmingham Railway Carriage and Wagon Company (BRCW), with Crompton Parkinson electrical equipment and Sulzer engines.

[11] In February 1958, the BTC approved the purchase of thirty-four Type 2 locomotives, but deferred a decision on 51 others due to be built in 1959, including twenty needed for Phase 2 of the electrification programme.

As Phase 2 of the electrification scheme had been implemented, the Southern Region set up the Traction Committee, which met for the first time on 15 December.

By this time, two locomotives had been transferred to the Eastern Region to work cement trains between Cliffe, Kent and Uddingston, Lanarkshire.

It was stated that the new timetable due for introduction in June had a substantial reduction in freight, which had only been recently decided upon and could not have been foreseen when the locomotives were ordered.

A meeting of Southern Region officials on 16 July discussed the exact information that the BTC required for the permanent reallocation of the spare locomotives.

As this was early days for ETH on BR, standards were not yet clear and there was a possibility in this region of a future need to heat continental stock from boat trains.

A third auxiliary generator of 57 kW was arranged similarly, to provide a supply for the traction motor cooling blowers, pumps, brake exhausters etc.

[14] There were twelve locomotives available,[16] enough to enable the class to be introduced to passenger trains, including the Man of Kent and Night Ferry.

[45] With the introduction of the winter timetable in September, the class were largely withdrawn from passenger service due to carriages still being heated by steam.

One of these trains, hauled by D6558, appeared in The Rank Organisation's 1963 film High, Wide and Faster, part of its documentary series Look at Life.

[20] In April, three locomotives were transferred to the South Western Division to work oil trains from Fawley Refinery, Hampshire.

This resulted in unpopular, complex run-round manoeuvres at termini as the Class 24 needed to be coupled inside to provide steam heat.

Weymouth trains started at London Waterloo powered by third-rail electric traction via Winchester and Southampton to Bournemouth.

This combination was not preferred, as it led to operational difficulties and inconvenience to waiting passengers who found themselves confronted with the side of the locomotive when their train drew to a halt.

The Type 3 power of Class 33/1 with only a 4 or 8 car train was rarely into the recovery margin of a schedule due to load.

Indeed, push-pull sets were a possibility over the entire range of Southern Region services including inter-regional trains; they were not infrequent visitors to Bristol Temple Meads and have been noted at Cardiff.

While third rail electrification was expanding on the Southern region, it was not then considered to be justified to extend beyond Bournemouth and so, in 1965, D6580 was fitted with experimental push-pull apparatus, high-level brake pipes and jumper cables to make it compatible with Multiple Unit stock.

Commencing 21 July 1965 tests were carried out between Wimbledon Park and Basingstoke and then, from 17 January 1966, on the Oxted Line, using a 6-coach rake of unpowered multiple unit coaches (designated TC, standing for Trailer Control).

It had a bell and beacon fitted at both ends above the lower-centre headcode lamp (along with SR style high-level brake pipes) which served to warn thoroughfare users and was controlled from the cab.

For main-line stock, two warning units were built and housed in a cabinet at the track side of the quay spur at the throat of the yard.

This equipment comprised a yellow control box with amber rotating beacon and bell which fitted on a bracket just above the rubbing plate on the cab front.

On arrival at the quay terminus the guard would move the warning equipment to the other end of the train in readiness for the return journey.

In later years, (e.g. for Railtours) the local police fulfilled the role of traffic control and the process of moving a train along the tramway became less routine.

A test train formed of 83301, 73205 London Chamber of Commerce, a Class 47/9 and 4TC set 8007 were used between Waterloo and Eastleigh, and between Stewarts Lane and Dover Western Docks.