Source: Norfolk Southern.

Railroad company Norfolk Southern (NYSE:NSC) has climbed to all-time highs throughout the past year, with shares almost doubling from their late-2012 lows. With the industry having recovered substantially in the past two years, Norfolk Southern has proved that there is room for railroad growth even when the coal industry isn't in peak condition. Let's take a closer look at some of the reasons that investors are so enthusiastic about Norfolk Southern and how its stock could continue to rise in the future.

1. Momentum in revenue and earnings has investors excited about Norfolk Southern stock.

One of the most promising aspects of Norfolk Southern's recent performance is that it has come from all corners of its extensive business. It's not a huge surprise to see areas like metals and construction perform well, especially given rising demand for materials, and gains in intermodal revenue reflect the ongoing high cost of diesel fuel for trucking that makes rail transportation so attractive from a cost-efficiency standpoint. But even Norfolk Southern's coal business saw gains in the company's most recent quarter, and given how much coal has held back the railroad industry's growth recently -- especially for Eastern-based railroads like Norfolk Southern and CSX -- good news in that division is cause for celebration.

Investors face the temptation of treating Norfolk Southern and other railroads as essentially interchangeable, with similar exposure to the macroeconomic conditions that affect the entire industry. But as competition picks up, being able to perform well will become increasingly important, and Norfolk Southern's track record of producing solid results even under less than ideal conditions gives investors confidence in its ability to keep moving forward into the future.

2. Coal could recover as natural gas prices rise and utilities replenish inventories.

Even though Norfolk Southern has relied on a wide range of sources of demand to help bolster its results, rising prospects for coal remain important to the railroad's long-term success. In 2012, natural gas prices fell to rock-bottom levels, and that led to a revolution in how electricity-generating utilities fueled their power plants. With the possibility of decades' worth of cheap natural gas becoming available due to the exploitation of shale oil and gas plays, utilities made huge capital expenditures to convert coal-fired power plants to use natural gas instead. Many concluded that this would be the death knell for coal use in the U.S. and leave railroads like Norfolk Southern running for cover.

Source: Norfolk Southern.

Now, though, supply and demand have returned toward equilibrium, and natural gas prices have stabilized and moved higher. Those utilities that retain their coal-fueled production facilities have largely run through their coal inventories, and that has many industry analysts expecting improving volumes of coal deliveries in the near future. Admittedly, any rebound in domestic coal use could prove short-lived, especially if natural gas doesn't climb further. Yet overseas demand for coal appears to be rising as well, and if Norfolk Southern can get its share of the export market, then it could benefit from coal's future strength for years to come.

3. Continued strength in the oil and gas industry could further Norfolk Southern's shipment volumes in that segment.

Source: Norfolk Southern.

Beyond coal, Norfolk Southern has done a reasonably good job of capitalizing on the next promising transportation opportunity: crude oil. Obviously, rivals CSX and Union Pacific have also sought to ship their share of crude in order to make up for lost opportunities in other areas, but Norfolk Southern believes that even after high-profile accidents involving crude-oil train derailments, railroads will continue to move crude from hard-to-reach areas of the country to ports and refineries on the coasts.

Norfolk Southern and its peers have also benefited from the demand from oil and gas exploration and production companies for the chemicals they need in order to use unconventional production methods like hydraulic fracturing. Even though oil prices have fallen recently, energy production activity doesn't appear to be suffering, and Norfolk Southern should still be able to count on favorable trends from the energy industry for at least a while longer.

With so many factors making Norfolk Southern look more attractive, it's easy to understand why the stock is near all-time highs. If those trends keep making the business stronger, then Norfolk Southern shares could have even more room to run.

Dan Caplinger has no position in any stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.