Many communities in the valleys will be without trains until next year as a major South Wales railway line closes at the end of April.
The rail route between Pontypridd and Treherbert will shut at the end of April for at least eight months.
It's due to work needed on the on the Treherbert Line as part of the latest phase of engineering work on the South Wales Metro.
During the lines transformation, Transport for Wales will be offering 50% off the cost of travel for people living in the Rhondda.
TFW have also announced a rail replacement bus service to try and minimise the disruption during the works.
It includes a timetable of one bus every 30 minutes stopping at all stations and a dedicated school support plan for Treorchy Comprehensive School.
Much of the work to be done on the Treherbert line will replace "mid-19th century" technology.
This includes old signalling systems and new station platforms at Treherbert, Ynyswen and Dinas Rhondda.
The Deputy Minister for Climate Change, Lee Waters asked for people to "bear with." He accepted the works will cause "disruption and inconvenience in the short term" but did emphasise that the "massive investment will make a huge difference to passengers."
The news has received a mixed reaction on social media with one Twitter user saying, "the people of Rhondda are paying the price not just for a decade of UK Government underinvestment in maintaining our transport links but in this case over a century."
Another user voiced their frustration at the TFW offer of 50% off travel, saying that all replacement services should be free.
Karl Gilmore, Transport for Wales, Rail Infrastructure Director said he understood the project will be hugely inconvenient while the line is closed but highlighted the upside of the development.
He said: “We know it’s going to be hugely inconvenient while the line is closed between April and early 2024.
"But transforming the dated railway line and bringing it right up-to-date will allow us to run more frequent and greener services, giving the people of the Rhondda a rail service they deserve."
Hailed as "another key milestone for the South Wales Metro project" the development is the latest in a list of significant investment into Wales' transport services.
The planned upgrade to the Treherbert line forms part of the South Wales Metro project's particular emphasis on the 'Core Valley Lines' running to Cardiff.
TFW said journey planning tools will be updated with the bus replacement information from 28 March.