Goods train operation on the branch ceased in 1968, but the line was electrified at 25 kV AC overhead in 1991 and now enjoys a regular ScotRail passenger service to Edinburgh.

The North British Railway obtained its authorising Act of Parliament in the 1844 session, to build a line from Edinburgh to Berwick (later known as Berwick-upon-Tweed).

The geographical position of North Berwick, and its lack of commercial significance at the time, meant that it was not to be on the main line, although it was a Royal Burgh with a population of 1,600.

[1] However, in the frenzied atmosphere of competition, the Directors became alarmed at the possibility of rival railways entering the area, and at this early date, abstracting traffic.

In addition, North Berwick was judged to have the potential for the construction of superior residential districts for Edinburgh merchants, who might travel daily to their place of business, by train.

In order to generate some income, the Board decided to open the line as far as Williamston,[a][6] The location was just short of the cutting.

A temporary wooden platform was provided there, and horse conveyances took passengers on to North Berwick; there were four trains daily (except Sundays).

[2] Efforts were made to encourage the high class residential traffic that had been originally contemplated, by offering very attractive season ticket rates to the first occupiers of new houses near the line.

The passenger service was reduced to two return trips daily by the horse-drawn vehicle (referred to as "the Dandy"), and the new arrangement started on 1 November 1856, as the winter traffic was light.

From about 1875 golf became of considerable popularity and began to bring traffic to the line, and in the season regular through trains from Edinburgh were put on.

In the late Victorian and Edwardian era, golf also became increasingly popular, and the practice of travelling some distance for a game became established.

The return service left Dunbar in the morning and picked up the North Berwick and Gullane portions at Drem and Longniddry, and it served breakfast.

They were not an unqualified success, but they continued operating part of the passenger service, running through from North Berwick to Edinburgh, until the late 1930s.

The branch was loss-making, and in attempt to revive it, British Railways implemented some modernisation schemes in the Edinburgh area, and diesel multiple unit trains were introduced on the branch passenger services from 23 July 1956, when a demonstration run took place, and from 3 February 1958 a recast diesel operated service ran on a regular interval basis, with all trains running to Edinburgh Waverley and some continuing to Corstorphine.

[1][3] In 1968 British Railways proposed complete closure of the branch on the ground that it was loss-making, but the Minister of Transport refused consent, and the line continued in use.

In October 1990 the Scottish section of the East Coast Main Line was electrified, and shortly before the day of switching on the power, agreement was reached between British Rail and Lothian Regional Council to share the cost of electrifying the North Berwick branch, at a cost of £1.3 million.

Finding rolling stock for the service was not easy, and after some research five units of class 305/2, built in 1960 and employed up until then in the London commuter area, were obtained.

Although the old electric multiple unit trains suffered reliability problems, and lacked air conditioning, their high-density seating layout abolished the overcrowding that had been experienced at peak times, and they proved surprisingly popular.