TIH Timeline Stories Archives - Tank Car Resource Center

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DOT Accepted ATCCRP Petition for Adoption of HM-246 Interim TIH Standard as Final

PHMSA accepted ATCCRP petition for adoption of the HM-246 interim TIH tank cars as the final TIH standard. The attached response was sent to the AAR.

CPC-1325 TCC Issued Six-Year Phase Out of Legacy TIH Cars

The AAR issued revisions to the TIH standard that required all tank cars in TIH service to meet HM-246 requirements by July 1, 2023. Tanks made from non-normalized steels must be removed from TIH service by July 1, 2029. [Read CPC-1325]

AAR Petitioned DOT for a Six-Year Phase Out of the Legacy TIH Fleet

Immediately following the ATCCRP Petition for a Final TIH Specification, the AAR petitioned PHMSA for a 6-year phase out of the legacy TIH Fleet. [Read the petition]

ATCCRP Petitioned the DOT to Adopt the Interim Standards as Final

Based on the ATCCRP research conclusions, industry stakeholders (including the RSI) petitioned PHMSA to make the interim standard (HM-246) a permanent standard for TIH service. [Read the petition]

The Advanced Tank Car Collaborative Research Program (ATCCRP) is Formed

The Advanced Tank Car Collaborative Research Program (ATCCRP) was initiated to coordinate research efforts to enhance the safety and security of rail tank car shipments of toxic inhalation hazard (TIH) materials. [Read more about the full background of the ATCCRP] 

HM-246 Interim TIH Standards Final Rule

Authorized the use of interim tank specifications for new construction of TIH cars DOT-105J500I, DOT-112J500I or DOT-105J600I, depending on commodity, and 9 mph rollover protection. These cars are limited to a 20-year regulatory life.

Next Generation Rail Tank Car (NGRTC) Project Concluded

Research on modeling forces in derailments and understanding of the performance of various design elements revealed that current designs involving multiple layers of steel performed best against smaller impactors. Additional research would continue under the Advanced Tank Car Collaborative Research Program (ATCCRP).

P-1525 Industry Petition for Interim TIH Standard

This industry petition from the American Chemistry Council (ACC), the American Short Line and Regional Railroad Association (ASLRRA), the Association of American Railroads (AAR), the Chlorine Institute (CI), and Railway Supply Institute (RSI) requested that the DOT consider interim TIH standards based on improved CPR (Conditional Probability of Release) measurements.

HM-246 Interim TIH Standard Proposal – NPRM

This NPRM proposed that cars built for TIH service be capable of surviving both head and shell puncture tests. These new designs had to be implemented within 8 years after the rule was finalized. See HM-246 NPRM

CPC-1187 Implementation of the AAR Standard for Tank Cars Transporting Toxic Inhalation Hazard (TIH) Commodities

The CPC-1187 circular issues by AAR required more robust tank specifications for anhydrous ammonia, chlorine and other TIH products. New car specifications included 9 mph rollover protection and a 10-year phase out of the legacy TIH Fleet.  CPC-1187