An unusual feature of freight operation on the line was the carriage of  gauge slate wagons (provided by the GWR) on standard gauge transporter wagons between  and Blaenau Ffestiniog where the wagons were off-loaded in the large station yard and their loads of dressed slate transferred to standard gauge GWR wagons for carriage back the way they had come then on via Manod and Bala.
Freight transport on this line involved a peculiar practice: gauge slate wagons (owned by GWR) were moved between and Blaenau Ffestiniog using standard gauge transporter wagons. The slate was unloaded at the large station yard, and then transferred to standard gauge GWR wagons for onward journey back to their origin point.