Doctor's Bridge or Machine Bridge at Pontypridd is a three-arched stone viaduct over the River Taff, extensively remodelled with later accretions and now carrying one carriageway of a road, which formerly carried Dr. Richard Griffiths' Tramroad (nprn 407018) connecting collieries in the Rhondda Valley, via the Doctor's Canal (nprn 85391), with the Glamorganshire Canal (nprn 34425). A weighing machine for coal trams was installed nearby hence the local name given to the bridge.
RCAHMW, 12 February 1992.