On the satellite photograph below, towards the bottom right hand corner, there is a pale line crossing diagonally from the 11th tee to the 9th fairway. This is the outline of the tramway linking the Ffrith line to the North Wales Coal and Oil Works and the Alyn Bank collieries on the other side of the river. The old rubble / stone track bed means that the ground dries out more quickly than the surrounding area so in dry weather the grass dies back leaving an ghost outline of the tramway line. There was an embankment crossing the 9th fairway, initially a gap was created in the embankment provide a way through to the green. Some years later the embankment was removed completely.
Below is the satellite photograph with the railway and tramways shown on the OS map overlaid. It can be seen that the 4th fairway was crossed by several lines as well as the sidings to Coppa Colliery. The tramway line across the 9th lines up perfectly with the ghost line on the fairway.