There were many companies producing whistles during the steam era.
Attachments:
C.M. McClung & Co 1921.jpg (354.99 KiB) Viewed 965 times
C. J. Rainear and Company 1953 2.jpg (79.55 KiB) Viewed 965 times
Barr_&_Creelman 1915 2.jpg (43.54 KiB) Viewed 965 times