Originally this was the terminus for passenger trains, though the line continued onward to the incline up to the slate quarry at Bryn Eglwys, and another incline down into the village. In 1976 this former mineral line was opened to passengers, though Abergynolwyn remains the principal station at the eastern end of the line as there are no facilities at , the current terminus.
As at Tywyn Wharf and all other stations, there is only one platform, on the north side of the line. When the line was extended it became necessary to accommodate two trains simultaneously, so the platform was extended in length, making it the longest narrow gauge railway platform in Britain at the time.
Abergynolwyn is Welsh for Mouth of the River with a Whirlpool.