Union Pacific railroad will release its third-quarter earnings report Thursday morning.

Investors will be looking closely at how much coal the Omaha-based railroad carried during the quarter. Two other major freight railroads, Norfolk Southern and CSX, have both reported continued weak coal demand because of the low natural gas prices and the mild winter.

Analysts surveyed by FactSet are expecting Union Pacific to report earnings per share of $2.18 on sales of $5.38 billion.

Railroad results are considered an indicator of the health of the economy. That's because the carloads of products and raw materials railroads carry can tell investors how other businesses are doing.

Union Pacific operates 32,400 miles of track in 23 states from the Midwest to the West and Gulf coasts.