The Port Mayacca RR bridge crosses the Okeechobee Waterway a short hop east of the Port Mayacca Lock. It's is a lift type bridge, and when fully raised, only provides 49 feet of vertical clearance. Many a sailor has cursed at this span, but others have gotten through by doing the "Okeechobee Limbo," a process of introducing artificial heel in a sailcraft, mostly by lashing water jugs to one side of the vessel, and then filling them until enough heel is produced.
Below, you will see that Captain Austin wants us all to know that this RR bridge is still in use, and is not "decrepit."

Subject: Port Mayacca RR Bridge
Cruising News: I get rather tired of hearing of the\\\"Old,decrepit RR bridge at Port Mayacca\\\". It is indeed fairly old,but it is part of a first class freight railroad,one that has just upgraded to heavy welded rail.The bridge is not decrepit,rather it is in regular use by the South Central Florida Express.Current use now may be mostly at night,but may increase if a proposed inland port is constructed near Clewiston.The bridge is on their line between Clewiston and Port St Lucie.
Addison Austin