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Trawsnewid Lein Treherbert

30 Mar 2023

Situated on the line connecting Treherbert and Cardiff, Ystrad Rhondda railway station holds one of the oldest pieces of equipment across our entire network. The ‘Token Exchange Signalling System’ currently used on the Treherbert Line was first introduced in Britain in the mid-19th century and some of the equipment still in use today is believed to date back to the 1930s.

As we move forward with our progress of building the South Wales Metro, we’ll be modernising this system, to ensure we have a reliable and efficient service. For this to happen we will need to close the line between Pontypridd and Treherbert, to carry out the significant work required on this section of the railway.


What is the Token Exchange Signalling System?

Railway signalling is a system used to control and manage the movement of railway traffic. The Token Exchange System is a form of railway signalling which uses a physical object (a token) to allow a train driver to enter a particular section of a single track.

Ystrad Rhonda is our token exchange point along the Rhondda Line. There are two tokens – a silver square token which is used on the journey between Ystrad and Treherbert, and a brass diamond token for the journey between Ystrad and Porth.

As the train travels from Porth to Ystrad, the driver will have a brass diamond token, allowing them to be the only train on the single line track between Porth and Ystrad. When they arrive at Ystrad Rhondda, they return the brass token, and collect a silver square token, which allows them to travel on the single track between Ystrad and Treherbert.

The tokens cannot be released if there is already a token being used by another train – only one silver, and one brass token are out on the line at any time, ensuring only one train is out on each section of the track at any time.



What is it being replaced with?

The Token Exchange System is being replaced with colour light signalling, the same system which we use across our network.  Working much the same way as traffic lights, colour light signals use red, green and yellow lights to let drivers know when to proceed, wait or stop.


Why is this change so important?

This major modernisation of the line will allow for more trains on our network, providing a more regular, efficient service between Treherbert and Pontypridd. Investment in the Metro will also allow for better connections between different types of transport, greater capacity, more accessible, quicker and greener services as well as significantly improving connectivity providing better access to jobs, leisure and other opportunities for the people of Wales.


Token exchange-07


Why is the line closed for so long?

Updating the Token Exchange System to an electric system is no small task and will include:

  • Diverting the huge gas and water mains which obstruct us from carrying out Overhead Line Equipment (OLE) works
  • Installing OLE equipment, this includes foundation piling works, mast installation and wiring
  • Building new station platforms at Treherbert, Ynsywen and Dinas Rhondda
  • Installing a new tracl along the line and a new passing loop between Ynsywen and Trherbert
  • Building a new footbridge at Ynsywen ad Dinas Rhondda
  • New and refurbished toilets, waiting rooms, shelters and the installation or upgrade of help points, CCTV cameras, Ticket Vending Machines (“TVMs”), smart ticket validators, Wi-Fi and Customer Information System (“CIS”) at Treherbert


What’s being done to the old Token System Exchange System?

We’re currently working with our Heritage & Sustainable Impact Manager to create an action plan, working with local heritage and history groups to look at ways we can collaboratively support moving forward both from a heritage and engagement perspective. 


Will there be a bus replacement service?

During the work, there'll be an enhanced rail replacement bus service for passengers. The rail replacement bus timetable will consist of: 

  • A core timetable pattern of one bus every 30 minutes, stopping at all stations. 
  • A semi-express AM and PM peak enhancement to reduce journey times and add capacity. 
  • A dedicated school plan for Treorchy Comprehensive school. 
  • Enhanced provision for special events including Christmas. 
  • Later-running services on Thursdays, Fridays and Saturdays from Cardiff Central straight up to the Rhondda valleys – approximately 45 minutes later than current rail service provision. 


Want to learn more about the South Wales Metro and what it means for you and your community? Visit our Metro page for more information: Metro | Transport for Wales (