Steam Whistle

I have a Steam Whistle that was on the St.Paul Park,Mn. Railroad bridge. My question is in the days that the steam boats would signal the bridge,The boat would blow a long whistle.The bridge would then respond with a signal.Was it just one long blast saying they would open the bridge or if they could not open the bridge ,maybe have 2 long or short.The Public Channel here is making a documetery on the History of the Bridge,and because I have that whistle on my Case Steam Engine,they want me to blow it like it was used in the early days.Many times I have heard the Delta Queen blow for the SPP bridge and it was always a long sound.Thanks for any information on this as I would like to blow it with steam just like the old days. Ted