Florida East Coast was acquired by Fortress and taken private in 2007. The hedge fund in 2016 reportedly had explored a sale of the regional carrier, which operates 350 miles of track between Miami and Jacksonville.
TRAC is the largest provider of intermodal chassis with 267,000 in its active fleet and 60 depots in North America.
Fortress also owns the Central Maine & Quebec Railway.
The terms of the deal approved by Fortress’ board represent a 38.6 percent premium on the stock price for shareholders.
Tokyo-based Softbank said senior management would remain in place as Fortress operates as an independent entity headquartered in New York. It has about $70 billion under management.
Softbank, owned by Masayoshi Son of Japan, has emerged as a major player in technology and communications, with $180 billion under management. It acquired control of telecom provider Sprint Corp. in 2013.
Subject to approval by Fortress shareholders and regulators, the transaction is expected to close in the second half of 2017.