[1] The main line, connecting Bucharest with the Hungarian border near Oradea, passes through Ploiești, Brașov, Sighișoara, Teiuș, and Cluj-Napoca.

The section between Bucharest and Ploiești is shared with CFR line 500.

In this context, the line is to be greatly upgraded, improving speed, capacity and interoperability (train lengths, ERTMS).

[2] The section between Câmpina and Predeal was upgraded between 2007 and 2011, bringing several improvements to the infrastructure along the route.

[3] Between 2012 and 2018, the Coșlariu–Sighișoara section was extensively upgraded to speeds of up to 160 km/h, including the construction of bridges and tunnels to straighten out the alignment of the railway.