The chord from the horn depends on a few things, first up is how the horn was cast, is the airflow restricted (many RRs now use a restricter in the air inlet), are the diaphragms in good condition and also the size of the bore affects it.
Many K5LAs sound different for these very reasons and hence you may hear reference to Amtrak tuned horns or Canadian tuned ones (the Canadian ones actually use different bells but are still K5 family for 5 chimes)
As K5 was mentioned this info is relevant to Nathan airchime
The managers in their ivory tower know more and more about less and less, and end up knowing everything about *&$% all