Will railroads be able to withstand future heat waves?

Railroad tracks start to buckle in extreme heat, and days with temperatures above 105° Fahrenheit are predicted to increase.

Railroads are essential in order to get bread on our shelves and packages to our front doors. Freight rail moves millions of tons of goods across state lines every day, ensuring that critical goods get to where they need to go, such as supplies to clinics and hospitals. Railroads are the most efficient way to move freight over land ( Association of American Railroads ). Passenger rail also shares the same tracks, which individuals rely on to get where they need to go.

But did you know:

  • railroad tracks buckle in extreme heat
  • extreme heat events are predicted to increase significantly

What is railroad buckling?

Like many materials, steel expands and curves when heated. Also, the way some tracks are currently laid, there is little room to expand, causing tracks to push against each other, resulting in warped tracks, commonly called "sun kink." Trains can no longer run at the current volume on warped tracks, and if left unrepaired, trains can derail. Read more from the U.S. Dept. of Transportation on  track buckling research. 

Recent incidents

The heat wave of July 2012 brought several rail incidents, according to the  Federal Register . Click on the map below to read about each incident:

Heat projections for the next few decades

The newly-released  Climate Mapping Resilience and Adaption (CMRA) data  show that even in the early century timeframe - defined as now until 2045 - there will be several areas of the country that will be too hot for railroads to operate as they currently do.

Like most projections-based data, CMRA presents ranges for various scenarios. We have a min, mean, and max number of days over 105° Fahrenheit in the early century timeframe for each of  two standard climate forecasting scenarios :

  1. Representative Concentration Pathway of 4.5 watts per sq. meter by 2100 (RCP 4.5), representing a "low-emissions" or best-case scenario
  2. Representative Concentration Pathway of 8.5 watts per sq. meter by 2100 (RCP 8.5), representing a "high-emissions" or business-as-usual scenario

With two different scenarios, three different time periods (early, mid, and late century), and three different statistics for each, we have 18 different maps that could be made. Imagine a line graph with a plume of uncertainty, something like this:

Comparing the minimum of the low-emissions scenario to the maximum of the high-emissions scenario for the mid-century timeframe can give us a sense of the lower- and upper-bounds in terms of areas that will need retrofitting. Let's find out which areas are likely to have heat events that put trains out of commission for 21 days (three weeks).

Implications & Adaptive Practices

By 2065, there will be several key railroads that will have 21 or more days (three weeks) of heat days over 105° Fahrenheit, even under the most conservative projections.

The good news is that adaptive practices are already taking place, particularly with respect to tract maintenance. "Track maintenance practices address the high thermal load problem by anchoring the rail at (neutral) temperature of 95 -110° F. This high neutral temperature range prevents the generation of excessively high buckling forces even when the rail temperatures reach 130 -150° F" ( U.S. Department of Transportation ).

The new Climate Mapping Resilence and Adaptation (CMRA) data can show us where the need for these adaptive practices is greatest: the Southwest, and Oklahoma/Kansas areas. Ultimately, the new CMRA data can help keep the lifelines of our supply chains running smoothly.

What maps will you make with this data?

This story map used the extreme heat measures, but this layer also contains similar attributes on other aspects of temperature, consecutive dry days, consecutive wet days, frost days, sea level rise, and more. The possibilities for maps and stories are endless.