In 1895 Naylor inherited Haggerston Castle and left Brynllywarch; the rolling stock of the railway was sold and the track was lifted.

In 1917 the government Timber Supply Department (which later became the Forestry Commission) relaid much of the tramway to serve the sawmill on the estate.

The railway and timber felling operations were mainly manned by German prisoners of war under military control.

The line closed again in 1922 and all the tracks lifted except the Lower Rhos to Pentre section.

This last remaining section was worked using an unknown 0-4-0 side tank locomotive for several more years.