It was opened from Clyde to Subiaco (later renamed Camellia) in January 1885, then by means of the construction of a bridge across the Parramatta River, to Carlingford in April 1896.

It closed on 5 January 2020 with most of the line converted to be part of Parramatta Light Rail which opened in December 2024.

The stations from Camellia to Carlingford consisted of a single platform of a sufficient length to accommodate four-carriage trains.

The new automatic crossings provide audible and visual warnings of an approaching train and a short time later close the metal gates.

Over the week of 20 to 26 October 2007, the section of track from Telopea to Carlingford was completely replaced, utilising concrete sleepers instead of timber ones.

A major problem was the level crossing over Parramatta Road, which held up traffic when trains travelled across it.

Proposals included tunnel links to Clyde or Granville stations, or replacing the line altogether with a more frequent light rail or busway service.

[17] The New South Wales Government originally planned for the Carlingford line to be part of Stage 2 of the Parramatta Rail Link.

Under the Rail Clearways Project, announced in 2004, the line was to have had a crossing loop at Rydalmere, thus allowing an increase in train frequency to half-hourly throughout the day.

In 2013, Parramatta City Council published a feasibility study into a Western Sydney Light Rail network.

[21] As a consequence, the Carlingford line north of Parramatta Road was closed on 5 January 2020 to allow conversion works to take place.

The short section between Clyde and the Parramatta Road level crossing will remain open to allow access to Sydney Trains' track inspection depot.

The original tracks and overhead wiring were removed in January 2020 with the stations at Rydalmere, Telopea, Camellia and Carlingford demolished from April to May 2020.

The only remnants of the original railway that were integrated with the light rail were the Parramatta River bridge at Rydalmere and the former Dundas station building.

Set M30 held the honour of running the final revenue service for the T6 Carlingford Line.