The line through Sea Mills has a speed limit of for locomotive-hauled trains and for diesel multiple units. The line handles less than 5 million train tonnes per year, has a loading gauge of W6 and a route availability of 7. , approximately 58,000 passengers used Sea Mills station, making it the 1,863rd busiest station in the country and the tenth busiest within the Bristol unitary authority area. This was an increase of almost 70% from the 2002-03 financial year, and reflected a general rise in usage of the Severn Beach Line.