While theoretically the whistle signals are the same for crews operating under the same rule book no two engineers blow them the same way. Go to any railroad terminal and the guys can tell who is on the engine by the way the whistle or horn sounds.
I am reminded of the young brakeman who asked the old conductor about whistle signals.
Brakeman- How long is a long and how short is a short?
Conductor- Well son that's all a matter of perspective.
Brakeman- What do you mean?
Conductor- Well what I call long my wife calls short.