Over at Pennsylvania HSR, Samuel Walker reminds us that the dominance of coal for US freight traffic slows down passenger trains, and this has a social cost in addition to the direct costs of coal mining and burning. But another post of his, regarding cant deficiency, suggests more problems coming from mixing modern passenger trains with very heavy freight. Coal trains slow all other traffic in three different ways, of which just one is the conventional schedule conflict, and even that means more than just slowing down intercity trains.
Schedule conflict reduces not just speed, but also span and punctuality. The Northstar Line in Minnesota shares track with BNSF’s Northern Transcon; since the line is freight-primary, there’s no room for off-peak service, and passenger trains can’t extend to the line’s natural terminus in St. Cloud, not without constructing additional tracks. Similarly, in Houston, plans for a commuter line to Galveston included peak-only service from the start.
Second, independently of scheduling, slow trains force faster trains to slow down by limiting the amount of superelevation that can be used. As a reminder: on curves, they bank the track, with the outer rail above the inner rail, to partly counter centrifugal force. If they do not cant the train enough, there’s cant deficiency; if they cant too much, there’s cant excess. Although there are strict limits for cant excess (in Sweden, 100 mm, or 70 on tighter curves), stricter than for cant deficiency (150 mm for a non-tilting passenger train, give or take), technically commuter trains could safely run at higher cant excess; however, for freight trains, high cant excess is unsafe because loads could shift, and the higher axle load means trains would chew up the inner track. Very heavy trains first require the track to have a lower minimum speed, and second have an even more limited cant excess because of the damage they’d cause to the track (about 2″, or 50 mm, in US practice). Walker links to a US standard guideline that uniformly assumes 3″ cant; greenfield high-speed lines go up to 180-200 mm.
And third, heavy freight trains damage tracks regardless. Coal trains also limit the amount of revenue the railroad gets out of each train, leaving limited money for maintenance, and are not time-sensitive, giving railroads no reason to perform adequate maintenance. To compensate, industry practices have to be less than perfect: cant and cant deficiency are less than the maximum permitted by right-of-way geometry and minimum speed, and freight railroads require barriers between their track and passenger track to protect from inevitable freight derailments. Even then the US safety level is well below what’s achieved anywhere else in the world with trustworthy statistics.
Of course, coal provides a great boon to the freight railroads. It’s a captive market. The railroads could price out coal and focus on higher-value intermodal traffic. Some of the lines that already focus on intermodal traffic are friendlier to passenger service, such as the FEC.
However, realistically, the end of coal is only going to come from environmental regulations. Those same regulations would apply to oil, inducing a mode shift from trucks to rail. The coal trains that would stop running would be replaced by trains carrying higher-value goods. The details depend on what the purpose and kind of environmental regulations are, but today’s environmental movement is heavily focused on climate change and not as concerned with local environmental justice, so loss of coal traffic due to a high carbon tax or local air pollution tax, both of which would also affect oil and gas, is much likelier than loss of coal traffic due to restrictions on mountaintop removal and air quality regulations at mining sites, which would not. (Of course oil causes plenty of damage to the biosphere, but the mainstream environmental movement is much more concerned with effects on humans than on other organisms.)
The political issue at hand, besides the easy to explain but hard to implement matter of avoiding catastrophic climate change, is what freight railroads are used to. Their entire business model is geared toward relatively low-value goods. A steep carbon tax is a risk: it should raise their mode share of total value of goods transported, which is currently 4% (see also figure 4.3 here), but it would come from a new set of goods, with requirements and challenges different from those of the current mix. The railroads would have to reintroduce fast freight, which most haven’t run in decades, and refine it to deal with the needs of shippers today. It’s not only a headache for the managers, but also a substantial risk of failure – perhaps rival railroads would be able to get all the traffic because they’d adapt to the new market faster, perhaps shippers would change their factory placement to move goods over shorter distances, perhaps they would not be able to cope with the immediate increase in fuel costs, etc.
Because of this, freight railroads may end up fighting a policy that would most likely benefit them. Although they represent a critical part of an emission reduction strategy, and are all too happy to point out that they consume much less fuel than trucks, fuel is a major cost to them, and coal is big business for them. These are not tech startups; these are conservative businesses that go back to the 19th century. Heavy coal trains then add a political cost as well: they help turn an industry that could be a major supporter of climate change legislation neutral or hostile to the idea.