Already in the 1860s, it was clear that the Mangfall Valley Railway (Mangfalltalbahn), which had been opened between 1854 and 1857, could no longer absorb the increase in traffic on the main lines towards Austria.

Duplication of the Mangfall Valley Railway was not an option due to its twisty and hilly route.

In addition, a new line via Grafing would be ten kilometres shorter than the Mangfall Valley Railway and it would also mean that locomotives would avoid wheel-slip because the slope was significantly more gradual.

[2] All trains now used the line through Grafing instead of the Mangfall Valley Railway, shortening travel time considerably.

At the same time additional tracks would be built in Munich East, Zorneding, Grafing, Ostermünchen and Rosenheim stations.

In 1917, only two pairs of expresses ran on the line, the others were cancelled due to lack of personnel, rolling stock, locomotives and coal.

The line was used for many military transports towards Eastern Europe and a delousing and "rehabilitation" facility was built in Rosenheim.

After the end of World War II, the track had to be rebuilt quickly as an important supply line.

[7] On 16 July 1945, a railway crash occurred at Aßling due to an error by a dispatcher in which a freight train carrying American tanks ran into a broken down passenger train carrying German prisoners of war and between 102 and 110 people were killed.

In the early 1950s, passenger traffic increased strongly and the line became an important link for migrant workers from Eastern Europe in the late 1950s.

[8] In 1991, regular interval services were introduced so that commuter trains ran hourly between Munich and Salzburg.

Since the 1990s, the section to Haar or Zorneding or Grafing station has been reinforced in the peak hour by an additional S-Bahn service, currently (since 2009) by line S6.

In addition, an hourly regional service runs from Munich to Kufstein, which serves all intermediate stops.

München Trudering station provides a connection with line 2 of the Munich U-Bahn towards Messestadt-Ost.

The station was provisionally put into operation at its present location in 1848, but it has been rebuilt several times since.

The current entrance building was opened on 1 August 1960, after the previous one had been destroyed in the Second World War.

Passenger operations ended eight years after the opening of the nearby Poccistraße U-Bahn station on 1 June 1985.

Today some S-Bahn line 6 services terminate in Zorneding during the peak; a siding has been provided for this purpose.

Thus, the station acts as an interchange between the S-Bahn, the Filzen-Express to Wasserburg and the regional trains on the Munich–Rosenheim railway.

The train was operated until December 2013 with a locomotive of class 111 and with double-deck carriages or Silberling coaches.

Bayerische Oberlandbahn has operated the services of the E-Netz Rosenheim, which includes the Munich–Salzburg, Munich–Kufstein and Munich–Holzkirchen–Rosenheim routes, under the brand name of Meridian since 15 December 2013.

Due to technical defects and lack of safety approvals until May 2014, the old trains were partly replaced by Silberling coaches of Deutsche Bahn, double-deck cars of Metronom and CityShuttle (push–pull) sets of the Austrian Federal Railways.

In addition, an Intercity train pair, branded as the Königssee runs from Hamburg to Berchtesgaden over this line.

EC and IC trains also operate between Munich, Rosenheim and Innsbruck on a basically two-hour cycle.

Several of these train pairs continue over the Brenner to Bolzano, Verona and Venice or Bologna.

Approximately 50 of these freight trains run on the line from Munich to Salzburg and continue towards Turkey, Greece, Ljubljana and Trieste.

These trains run mostly from Munich East marshalling yard to Verona (Brenner traffic) and are operated by TX Logistik.

The Federal Transport Plan (Bundesverkehrswegeplan) for 2030 includes a double-track new line from Grafing to Brannenburg via Großkarolinenfeld with a design speed of 230 km/h.

This route is part of the Trans-European Transport Networks (TEN-T) line 17 from Paris to Budapest.

A rear-end collision occurred at line kilometre 43.2 at Elkofen, between the stations of Aßling and Grafing, on 16 July 1945 at 21:40.