Jack Koraleski likes to imagine what Abraham Lincoln would think of the railroad he helped create a century and a half ago.

What began with laborers on a grueling westward push through wilderness is now a complex, high-tech network. The city that saw the railroad's first spikes is now home to Union Pacific's eight-year-old headquarters tower and a dispatch center. From Omaha, some of the railroad's 44,000 workers can monitor trains moving across a 23-state network, detect safety problems in trains hundreds of miles away and talk to customers as far away as China.

Lincoln would see a company that's become the largest railroad in North America, one that operates 8,200 locomotives over 31,900 route miles and finished last year with a net income of $3.3 billion and increasing returns for shareholders.

And he'd find a railroad that, in this milestone anniversary year, says it is poised to continue its strong streak - though it will face plenty of new challenges, from strong competition to new leadership to significant ups and downs in some of its biggest business categories.