PHMSA Final Rule on HHFT – Speed Limits

This is part of a continuing look at the recently published final rule on highly-hazardous flammable trains (HHFT; HM-251). Earlier posts in the series include

DOT and Canadian Transport Ministry Announce New HHFT Final Rule

PHMSA Final Rule on HHFT – Route Selection

In this post I’ll look at the speed limit requirements set forth in this final rule. As with many of the requirements these speed limits only apply to HHFT. As a reminder, the rule defines an HHFT as:

∙ A single train transporting 20 or more loaded tank cars containing Class 3 flammable liquid in a continuous block; or

∙ A single train carrying 35 or more loaded tank cars of a Class 3 flammable liquid throughout the train consist.

Pre-Rule Speed Limits

The preamble to the rule explains that, in general the current regulations establish train speed limits based upon track classifications with a maximum speed limit on the best track for freight trains set at 80 mph. Design specifications from the Association of American Railroads (AAR) set a practical limit of 70 mph.

Railroad protocols for the transportation of hazardous materials set an even lower speed limit. The preamble notes that AAR Circular OT-55-N includes a 50-mph maximum speed for any “key train,” including any train with 20 car loads of “any combination of hazardous material.” In February of last year railroads further agreed to limit the speed of crude oil trains to 40 mph in High Threat Urban Areas (HTUA; see 49 CFR 1580.3, list, maps).

The Options

Last summer the notice of proposed rulemaking (NPRM) for this rulemaking proposed changes to the speed limit requirements. The first was to make official the 50 mph speed limit for HHFT. Then they offered three options for further speed reductions for HHFT that contained even one rail car that did not meet the new DOT 117 standards:

Option 1 – 40 mph limit in all areas;

Option 2 – 40 mph in urban areas with a population of greater than 100,000 people;

Option 3 – 40 mph in HTUA

Finally PHMSA proposed an even lower speed limit (30 mph) in HTUA if the train did not meet the Advanced Brake Signal Propagation Systems described in the NPRM.

The preamble to the final rule provides a detailed discussion of the more than 90,000 public comments received on the NPRM speed proposals as well as the different speed limits proposed in some of those comments.

Final Standards

In the end it came down to the cost benefit analysis required of the agency by federal law. In this case, faster speeds meant lower costs but increased accidents and consequences. Lower speeds meant fewer accidents and reduced consequences.

In the new 49 CFR 174.310 PHMSA added paragraphs describing the speed restrictions for HHFT. Section 174.310(a)(2) sets the 50 mph speed limit for all HHFT and a 40 mph speed limit for any HHFT that contains a loaded with a Class 3 Flammable Liquid that does not meet the DOT 117, DOT 117P, or DOT 117R standards.

Additional speed limitations are set for trains not equipped with specific breaking systems. Section 174.310(a)(3)(i) requires that any train not equipped and operated with either a two-way end-of-train (EOT) device, or a distributed power (DP) system has a maximum speed limit of 30 mph.

Section 174.310(a)(3)(ii) includes a new train designation, highly-hazardous flammable unit train (HHFT with 70 or more flammable rail cars of which at least one is PG I). HHFUT are limited to 30 mph after January 1^st, 2021 unless the train is equipped with ECP brakes, except for buffer cars, and must be operated in ECP brake mode.