This whistle is a single chime also known as a bell whistle. My particular recording's whistle was made for a T class and is currently owned by a NRM volunteer. The whistle has been put on Bub and Perrone before, but this particular recording came from Perronne. The SAR T, P and F class locomotives all used and were built with this type of whistle. Some of these locos had their original whistles replaced for Nathan 6 chimes, fitted to them later in life. The recording is my own and was recorded in July 2020. The bell sound is courtesy of Caleb Jenkins, who has kindly given permission to use it in this hornsound. If you would like to contact him, his YT channel is Caleb's Rail Films.