The R1 is a line of Rodalies de Catalunya's Barcelona commuter rail service, operated by Renfe Operadora.

It runs northwards from the Barcelona area to the southern limits of the province of Girona, passing through the coastal Maresme region.

In the long-term future, it is projected that the R1 will take over the southern section of line R2, creating a major north–south axis that will extend along the coast of the Barcelona metropolitan area.

The current line scheme of the R1 started operating on 28 May 1989 (1989-05-28), after the dismantling of the former route of the Barcelona–Mataró–Maçanet-Massanes railway through the Barcelona neighborhood of Poblenou.

[12] These services moved their southern terminus from the airport to Molins de Rei, originating the line's current termini.

[15] Like the rest of Rodalies de Catalunya lines, the R1–RG1 runs on the Iberian gauge mainline railway system, which is owned by Adif, an agency of the Spanish government.

The R1–RG1 operates on a total line length of 181.2 kilometres (112.6 mi),[3] which is entirely double-track, excepting for the single-track section between Arenys de Mar and Maçanet-Massanes stations.

After Arc de Triomf, they branch off to El Clot-Aragó railway station, running on exclusive tracks from this point on to Maçanet-Massanes.

ERTMS Level 2 will be installed on the 56-kilometre-long (35 mi) section between L'Hospitalet de Llobregat and Mataró, increasing capacity and reliability parameters.

[25] Moreover, the R1 does not operate south of L'Hospitalet de Llobregat on weekends, when this section is solely served by Barcelona commuter rail service line R4.

[1][27] Civia trains have been running on the line since July 2006, initially only operating services between Molins de Rei and Calella.