The electrification of the Cardiff-Rhymney railway line should be completed by autumn 2025.

In an update on the ongoing works, Transport for Wales said it was installing overhead line equipment, which once completed will power “cleaner, greener and quieter” electric trains.

Workers are currently creating the foundations for overhead gantries and are moving northwards along the line “over the coming weeks”.

The majority of this work is happening overnight, which TfW admitted could cause noise problems but said the project “will be worth the short-term disruption”.

The line improvements form part of the wider South Wales Metro project, which is part funded by the Cardiff Capital Region partnership of ten councils in the south-east of Wales.

Transport for Wales said the electrification works south of Caerphilly station, connecting the town to the capital, should be completed “towards the end of this year”.

Meanwhile, improvements to the remaining section of the line, between Caerphilly and Rhymney, is “ongoing and due for completion in autumn 2025”, the firm added.

So-called “piling” works, to create the foundations for the electrification equipment, are currently under way between Llanbradach and Ystrad Mynach.

This overnight work means buses replace trains on the route later in the evenings, currently for five days each week.

Transport for Wales said it would “limit the impact of the work on the peak travel times. and will continue to do so where possible”.

It also acknowledged the works could “cause disruption to those living close to the railway line”, adding that “our teams will do their best to keep noise to a minimum where possible”.

“We would like to assure customers that the project will be worth the short-term disruption for the significantly improved service long term, and in the meantime we encourage customers to check their journey details before travel,” a spokesperson for the firm added.