Owners of power plants have a significant new option to factor into their natural gas-related plans, thanks to a newly finalized rule from the Pipelines and Hazardous Materials Safety Administration (PHMSA).

Following a couple years of development, public comment and revision, the PHMSA — in conjunction with the Federal Railroad Administration — has established standards that will allow the bulk transport of liquefied natural gas (LNG) in specialized rail tank cars. The final rule was issued on June 19, 2020.

Regulating the Rails

The regulation grants approval for LNG transport in DOT-113C120W tank cars, which will have an enhanced outer tank that is thicker and made of steel with a greater puncture resistance than standard DOT-113 cars in order to reduce the likelihood of the outer shell being compromised if the train were to be in an accident or derail.

Other significant features of the final rule include:

  • Trains with more than 20 loaded LNG cars in a continuous block, or more than 35 total throughout the train, require enhanced braking mechanisms.
  • The LNG tanks must have remote monitoring for pressure and location (compliant with §172.820 route planning requirements). Each tank’s pressure is allowed to increase from a loading pressure of 15 psig to a maximum of 75 psig. Limits were based on 20-day transportation with average pressure rise of 3 psig per day (the average industry experience is 0.75-1.5 psi/day). If delivery will take longer than 20 days, this must be communicated to the proper authorities.
  • Trains carrying LNG will have route analysis completed to evaluate safety and security.

The intent of the rule is to allow natural gas resources in the U.S. that lack access to pipelines or ports the means for delivery of natural gas to both domestic and international markets, such as Mexico. It also aims to treat LNG similarly to other cryogenic liquids already being transported by rail across the U.S. However, the remote monitoring and route analysis provisioned under this rule are not currently required on other trains carrying flammable cryogenic material, thus setting stricter safety standards for LNG than other hydrocarbons already being transported by rail.

The final rule, which will take effect 30 days after being published in the Federal Register, effectively enables an alternative transportation option to gas pipelines already operating at or near capacity. While LNG also can be transported by truck, the ability to move it by rail should make bulk shipments over land much more economical.

Leveraging Existing Infrastructure

With growing interest in LNG as a fuel alternative at power generation facilities, logistics have been one of the most significant hurdles for plant owners. However, many legacy plants have existing rail spurs that have been used to deliver coal in the past. The ability to deliver LNG in bulk quantities in a safe and cost-effective manner should give these owners more flexibility as they consider their fuel options.

It may take some time to build and deploy the specialized rail cars needed to transport LNG by rail in the wake of the final rule, but the option should play an increasing role in planning and business case development, especially for sites with existing rail infrastructure. Some owners were likely already developing plans that were contingent upon the rule being finalized; they now have that confirmation and may lead the way in implementation.


Our recent webinar gives you a solid grounding in the design considerations and the possibilities for storage and transportation of LNG.

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Sara O’Dell, PE, is an associate project engineer with nearly 20 years of engineer-procure-construct (EPC) project execution experience, spending the last 15 years working on LNG projects using both liquefaction and regasification processes for onshore and floating installations.