Kirby Corporation (KEX) , the largest publicly-traded shipping company in the services sector with some $5 billion of market-share, was trading three-quarters of a percent lower on Monday after releasing its earnings statement for the recently-ended period.

The transporter of petro and agricultural chemicals reported net income of $69.1 million, or $1.21 per share on revenue of $551.1 million, in contrast to the prior-year period during which Kirby earned $53.1 million, or $0.95 per share on revenue of $521 million. The results bested street expectations for earnings of $1.12 on a per share basis, though came short of revenue predictions of $574.30 million.

Houston, Texas-based Kirby is a maritime transporter of agricultural and petrochemicals, a business it supplements with its diesel engine/oilfield services segment. The company has struggled particularly in its engine segment, where continued underperformance was explained in the most optimistic terms by CEO Joe Pyne: "For both our inland and coastal marine transportation markets, strong demand, high tank barge utilization levels and favorable pricing trends continued during the third quarter. However, our land-based diesel engine services business continues to be very challenging. The significant increase in pressure pumping horsepower during 2010, 2011 and early 2012, along with current low natural gas prices, resulted in a very weak market for our land-based diesel engine services sector. However, there are signs that this cycle has bottomed and we anticipate an improved market sometime in 2014."

According to the company’s income statement, however, the results are far more striking. On a year-over-year basis, revenue for the diesel engine segment had declined from $171.6 million to $114.9 million. Operating income also suffered, dropping from $14.6 million in the prior year period to just over $9 million in the recently-ended one that relied almost entirely on a $7.9 million tax-credit related to its April 2011 acquisition of United Holdings LLC.

Business was brisk in the marine transportation segment however, with revenue at $436.2 million compared to $349.8 million a year ago, and operating income up from $81.7 million to $113.6 million.

Kirby also announced that it expected EPS in a range of $1.05 to $1.15 in Q4, but reduced its full-year 2013 outlook from a forecast of $4.37 to $4.47 per share to $4.15 to $4.35 per share. The company’s shares opened at $92.00, just $0.39 shy of its 52-week high, but had dipped 0.86 percent to $89.72 ahead of the closing bell.