I found this collection reference on the Prince Edward Island Provincial Archives website:
The collection consists of 15 images of trains in operation in the eastern section of Prince Edward Island between 1949 and 1978. There are multiple copies of some images. Of particular note are photographs of the bridge over the Pisquid River between Mt. Stewart and Lake Verde and the station at Mt. Stewart. The collection also contains 7 original negatives which correspond to the images. Images identified by the photographer/donor.