American Routes: Horn & Bell Use Regulations

Does anyone know, or can point me in the direction of where I can learn about the protocols of using the bell & horn on American routes?

Does this change depending on what route you are driving?

 

https://steamcommunity.com/sharedfiles/filedetails/?id=400748122

 

For American freight, if it's like the drivers in my local area (CN GP38s and AC4400CW) just pull the handle and hold it - haha

 

Read through the NORAC Operating Rules