In 1888 the railway became a public limited company, Salzburger Railroad and Tramwaygesellschaft (SETG). Work started building the "Northern Extension" to Lamprectshausen, the first section opening on 20 January 1886.

In 1907 the line was extended southwards again, across the international border to Berchesgarten, and the section of line was jointly run by SETG and the Bavarian State Railway, the königlich bayrische Staatsbahn. When the southern line was electrified in the same year, the German railway also purchased electric vehicles, and ran services into the centre of Salzburg. The northern line, however, was not electrified at this time. The main line continued with passenger and goods traffic (there were even goods electric cars) until 1947, when the line was absorbed by the city, as Salzburger Verkehrsbetriebe SVB. Five years later the city, under pressure to sort out the traffic problems following the great increase in private traffic after the end of World War 2, closed the southern section of the SVB, from the Hauptbahnhof to Berchesgarten, the tramways in the city, and the connection from Parsch, leaving only the Northern Extension.

The line from Salzburg Hbf., ran using steam locomotives hauling large amounts of goods traffic, and a smaller amount of passenger services, right up to 1950, when the last section of line was electrified. The process of electrification had started in 1923, the line as far as Bergheim being wired from 1927. A trial using a gas-electric railcar ended in 1944 when it caught fire. After the closure of the main line, most of the electric railcars and small steeple-cab locomotives were transferred to the northern line.

Following the opening of a lignite (brown coal) mine at Lamprectshausen, the line became ever more busy with freight traffic. Trains from the mine had to reverse at Burmoos before continuing their journey. Two more electric locos were purchased to cope with the coal traffic.

The Trimmelkam - Burmoos line was run by SAKOG, a part of Stern und Hafferl, as a branch line, in between the goods traffic. Photos of the line and its stock in S&H times and subsequently.

In the 1970's the line, sorely rundown and with life-expired equipment, was proposed for closure, but instead a programme of renewal was decided upon. New stock of articulated railcars, were purchased, and passenger numbers doubled, and doubled again, in the four years at the start of the 1980's. More vehicles arrived in 1994, the same year that the Burmoos line was absorbed into the company, which then became the Salzburger Lokalbahn, or SLB, part of Salzburger Verkehrsverbund. Following the closure of the lignite mine, a power station was built on the site, and coal now travels in the opposite direction, trains still reversing at Burmoos.

More recently, the northern terminus at Trimmelkam has become Reidersbach, whilst a new station, nearer the town centre, has been built on the mine goods sidings beyond the former terminal.

In order to alleviate traffic problems in front of the Hauptbahnhof at Salzburg, the whole of the area was changed in 2000/2001, with new underground car parking, a new trolleybus and bus station, and the removal of the SLB station in favour of an underground station. This new station, under the front of the Hauptbahnhof, has been built as a through station in order to provide for future extensions towards the Old Town, back towards the south of the city.

A short private NG line is adjacent to the SLB at Irlach.

The SLB run nostalgic trips along the main route, using some of the vehicles built for the main line - the "Roten Elektrischen" or Red Electrics. Extra services, using the original 1907-built railcars and trailers, are provided to Oberndorf in the period up to Christmas, and for the special Christmas Eve open air service there.

The OGEG operate occasional steam services on the Trimmelkam - Burmoos route, and the opportunity has been taken in the past to use large steam locomotives to haul the heavy coal trains to Reidersbach - indeed a shortage of electric traction has made this an occasional necessity. Information and links regarding steam excursions are available via the ARG webpage called "Vintage Rail Tourism".