The entrance sign to BNSF railway corporate headquarters campus in Fort Worth.

FORT WORTH (AP) — The Burlington Northern Santa Fe railroad plans to invest $3.9 billion in upgrades to its network this year.

The railroad said Wednesday that its capital spending plan is $400 million bigger than its 2011 budget of $3.5 billion. Overall, the nation’s major freight railroads, which include BNSF, plan to spend about $13 billion this year, up from 2011′s $12 billion, as the economy improves.

BNSF says most of its spending — $2.1 billion — will upgrade its core rail network. Another $1.1 billion will be spent on locomotives, freight cars and other equipment. About $300 million will be spent on developing the federally mandated system to remotely stop trains headed for a collision.

The Fort Worth based railroad is owned by Warren Buffett’s Omaha-based Berkshire Hathaway Inc.

(Copyright 2012 by The Associated Press.  All Rights Reserved.)