GATX Corp, the Chicago-based lessor of freight cars, is offering more than US$3 billion for General Electric Co's Rail Services unit, people familiar with the matter said.

GATX is the leading bidder for the unit, which has a book value of about US$2.8 billion, the people said. The terms are still being negotiated, said the people, who asked not to be identified because the discussions are private. One said the offer may be as much as US$3.5 billion.

Chief Executive Officer Brian Kenney is building GATX's rail business after selling an aircraft-leasing division in 2006. At GE, whose stock has slumped 20 percent this year, CEO Jeffrey Immelt is seeking to shed as much as US$100 billion in slower-growing finance assets such as the rail leasing division.

More investments

During a July 24 teleconference, GATX's Kenney said he's seeking to "invest more aggressively" during a financial slowdown.

"That's certainly what we prepared the company for over the last couple of years," said Kenney, according to a transcript of the July call.

Connecticut-based GE is the world's biggest maker of jet engines, locomotives, medical imaging machines and power-generation equipment. Its Website says the rail division leases railcars and trailers, containers and chassis to rail lines and shippers. The unit is based in Chicago and has offices in Canada, the United States and Mexico.

Immelt, 52, has sold slower-growing and capital-intensive businesses such as insurance and plastics for more than US$55 billion since 2001.