In 1898 it was sold to the British Electric Traction Company, but their attempt to get local authority approval to extend and electrify the line failed.
The tramway closed unexpectedly in February 1902, when an outbreak of the infectious disease glanders resulted in most of the horses dying.
A second route between Porth and Partridge Road opened on 5 November, passing through Penygraig and Tonypandy, on the south side of the River Rhondda.
[4] The extra milage resulted in four additional double-deck tramcars being purchased from Brush in 1913, but unlike the earlier vehicles, the upper deck was covered.
This proved sufficiently popular with passengers that a programme of fitting covers to the older tramcars began, and by the end, most had been upgraded.
[6] The neighbouring Llantrisant and Llantwit Fardre Rural District Council had obtained an Act of Parliament in 1912 to authorise a light railway to link Tonyrefail and Gilfach Goch to Williamstown, which was served by trams from 30 March 1912.
[5] At a time when shafts were being regularly sunk to open up new coal mines, there was a need for a flexible transport system to service the new pits, but extending and diverting a tramway was too expensive for this to be viable.
The opening of additional pits at Glifach Goch in 1911 and 1912 resulted in a proposal to run a connecting motor bus service from Williamstown to the area.
However, the Manager and Engineer for Rhondda Transport, H J Nisbett became interested in railless traction, and after a visit to the newly-opened Rotherham trolleybus system, he succeeded in persuading the council that this was a better solution.
[5] P E Stanley, the chief engineer for the National Electric Construction Company, researched the merits of the three methods of current collection then available.
This enabled them to run the trolleybuses from the depot to the start of the route along the tram lines, using one of the trolley poles and a skate that ran along the tramway rails.