# TCIX Rail — Hazardous Materials Safety Interpretation

- **operation:** document
- **citation:** 21-0054
- **title:** TCIX Rail — Hazardous Materials Safety Interpretation
- **source type:** guidance
- **agency:** Pipeline and Hazardous Materials Safety Administration
- **status:** guidance
- **official:** true
- **published on:** 2021-08-25
- **effective on:** Not available
- **summary:** 21-0054 response to TCIX Rail concerning 179.13, 179.201, 180.509.
- **machine formats:** - **json:** https://regulus.evalyn.ai/document/phmsa-interpretation-21-0054.json
- **markdown:** https://regulus.evalyn.ai/document/phmsa-interpretation-21-0054.md
- **app url:** https://regulus.evalyn.ai/document/phmsa-interpretation-21-0054
- **source url:** https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/docs/standards-rulemaking/hazmat/interpretations/75806/210054.pdf
**body:**

<<<PAGE 1>>>

U.S. Department
of Transportation
Pipeline and Hazardous
Materials Safety
Administration
1200 New Jersey Avenue, SE
Washington, DC 20590
August 25, 2021
Keenan Moore
Fleet Management Specialist
TCIX Rail
911 NW Loop 281 Suite 316
Longview, TX 75604
Reference No. 21-0054
Dear Mr. Moore:
This letter is in response to your March 26, 2021, email requesting clarification of the Hazardous
Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to minimum plate thickness
requirements for DOT-111 tank cars. Specifically, you ask what minimum plate thickness
should be used when determining the permitted thickness reduction adjustments in accordance
with § 180.509 and the Association of American Railroads (AAR) Manual of Standards and
Recommended Practices (MSRP) Section C-III Specifications for Tank Cars (M-1002).
You state that you use the minimum plate thickness provided in § 179.201-1 for DOT-111 cars;
however, you note that the MSRP has additional thickness requirements listed for tank cars
constructed after 2004, based on how the tank car is equipped (e.g., shell material type, jacket,
head shield, etc.).
We have paraphrased and answered your questions as follows:
Q1. You ask what minimum plate thickness should be used when calculating permitted
thickness reductions in accordance with the thickness test requirements provided in
§ 180.509(f).
A1. For compliance with the HMR, and for tank cars that do not exceed 263,000 pounds
gross weight on rail, the thickness values in § 179.201-1 of the HMR must be used to
calculate the required minimum tank shell or head thickness, or value “B,” as provided in
§ 180.509(f). As authorized by the Federal Railroad Administration (FRA), tank cars that
have a gross weight on rail up to 286,000 pounds must adhere to the requirements
specified in the approval notice titled “Operating Certain Railroad Tank Cars in Excess of
263,000 Pounds Gross Rail Load” (76 FR 4250). Note that the AAR may have additional
minimum thickness requirements for the use of interchange railroads. You may use the
contact information provided below to confirm AAR’s tank car requirements.

<<<PAGE 2>>>

Q2. In the event that the specifications provided in Chapter 2 of M-1002 must be used as the
“required minimum tank shell or head thickness after forming,” you ask whether PHMSA
would develop new specification classes that include those additional requirements (e.g.,
shell material type, jacket, head shield)—similar to what is provided in the specification
table provided in § 179.201-1—or if those specifications would become grandfathered
requirements that would result in noncompliant cars being phased out as they reach their
50-year end of life period.
A2. The answer is no. Except for tank cars containing poisonous-by-inhalation material, the
requirements for a tank car exceeding 263,000 pounds are currently provided in
§ 179.13(a). No new specification is needed, as the tank cars built to AAR S-286 meet
the DOT specification minimum thickness requirement.
Q3. You ask whether there would be a difference in the interpretation of the minimum
thickness requirements between PHMSA and AAR that might result in noncompliance
findings from Bureau of Explosives/ Transportation Technology Center, Inc.
(BOE/TTCI) auditors and the FRA to various parties, depending on how they interpret
these requirements.
A3. A PHMSA Letter of Interpretation—such as this letter—is intended to clarify the HMR
and is not used to determine compliance with the regulations. Noncompliance findings
cannot be determined within the scope of a letter and are not established for tank car
specification compliance by this Office. The FRA Tank Car Team, Motive Power and
Equipment (MP&E) Division and AAR’s BOE/TTCI auditors should be contacted
regarding their individual enforcement policies for a nonconforming tank car. The FRA
Tank Car Team can be reached by email at hmassist@dot.gov, and a list of AAR points of
contact is available at. https://aar.com/standards/boe_contacts.html.
I hope this information is helpful. Please contact us if we can be of further assistance.
Sincerely,
Dirk Der Kinderen
Chief, Standards Development Branch
Standards and Rulemaking Division

<<<PAGE 3>>>

Casey
21-0054
From: INFOCNTR (PHMSA)
To: Dodd, Alice (PHMSA)
Cc: Hazmat Interps
Subject: FW: 2004+ 286K DOT-111 Minimum Thickness Question
Date: Wednesday, May 19, 2021 4:55:04 PM
Attachments: image003.png
image009.png
image011.png
Hi Alice,
Please see below for an interpretation request.
Is it possible to assign this request to Leonard Majors or Alex Cheng in PHH-22? They were the primary people
spearheading the research in Keenan’s question.
Please let me know if you have any questions.
Regards,
-Breanna
From: Keenan Moore [mailto:keenan@trinitychem.com]
Sent: Wednesday, May 19, 2021 1:34 PM
To: INFOCNTR (PHMSA) <INFOCNTR.INFOCNTR@dot.gov>
Subject: RE: 2004+ 286K DOT-111 Minimum Thickness Question
CAUTION: This email originated from outside of the Department of Transportation (DOT). Do not click on links or open
attachments unless you recognize the sender and know the content is safe.
Breanna,
Please see Physical Mailing address below. Thank you all for your help.
911 NW Loop 281 Suite 316 Longview, Texas 75604
Please & Thank You,
Keenan Moore
Fleet Management Specialist
Keenan@TCIXRail.com
Office: (903) 653-4077
Cell: (903) 241-4079
From: INFOCNTR (PHMSA) <INFOCNTR.INFOCNTR@dot.gov>
Sent: Tuesday, May 18, 2021 3:08 PM

<<<PAGE 4>>>

To: Keenan Moore <keenan@trinitychem.com>
Subject: RE: 2004+ 286K DOT-111 Minimum Thickness Question
Dear Keenan,
We have received your request for a written letter of interpretation regarding the hazardous materials regulations
(49 CFR Parts 171-180). The hazardous materials regulations are available at the following URL:
https://www.ecfr.gov/cgi-bin/text-idx?
SID=1d49a3b137cb1b6fc45251074e634b44&tpl=/ecfrbrowse/Title49/49tab_02.tpl
However, before we can submit your request for processing, please respond to this email with:
Physical Mailing Address
Sincerely,
Breanna, Hazardous Materials Specialist
An e-mail response from this office is considered informal guidance. Formal guidance may be requested in
accordance with 49 CFR 105.20. https://www.phmsa.dot.gov/standards-rulemaking/hazmat/hazardous-materials-
information-center
From: Keenan Moore [mailto:keenan@trinitychem.com]
Sent: Friday, March 26, 2021 10:08 AM
To: INFOCNTR (PHMSA) <INFOCNTR.INFOCNTR@dot.gov>
Cc: Fleet Management <fleetmanagement@trinitychem.com>
Subject: 2004+ 286K DOT-111 Minimum Thickness Question
CAUTION: This email originated from outside of the Department of Transportation (DOT). Do not click on links or open attachments
unless you recognize the sender and know the content is safe.
Breanna,
Please see relevant sections of the CFR and MSRP C-3-Chapter-2 below and attached. My question is what
minimum plate thickness should be used when calculating reductions allowed per CFR49.180.509(f). This amounts
to what thickness should be used for item “B”. Typically, I would use the highlighted column (Minimum plate
thickness) below from 179.201-1 (For DOT-111 cars), but MSRP C3-Chapter2-2.5.3, has additional thickness
requirements listed for newer (2004+) cars depending on how else the car is equipped (shell material type, jacket,
head shield). Are these thicknesses from Chapter 2 to be used in this calculation as item B or should the 179.201-
1 table below be used as item B, making the Chapter 2 thickness an item A (overpackaged with additional
thickness)?

<<<PAGE 5>>>

A few additional thoughts.
If Chapter 2 is to be used as item B for the calculation, then shouldn’t that result in new DOT Specification classes
that require those additional requirements (shell material type, jacket, head shield) similarly to the 179.201-1
specification table below specifically the last “References” Column? Or make reference to Chapter 2-2.5.2.3 in
180.509(f) Fig A for a reminder to what minimum plate thickness should be used for certain cars.
Or is this considered a type of grandfathered requirement that will result in noncompliant cars (less than 2004
ordered) being phased out over time as they reach their 50yr EOL? Which would eventually require the 179.201-1
table thickness being revised by 2054 to match the Chapter 2 thickness (for cars that are 286K).
Will there be a difference in opinion between the Feds and the AAR regarding how this is handled, resulting in
noncompliance findings (from BOE/TTCI auditors and the FRA) to various parties depending on how they interpret
this?
C3-App D-2.1.8.2 Fig.D.1 does not mention Chapter 2 thicknesses and only specifies the 179.201-1 table.

<<<PAGE 6>>>

§179.201-1 Individual specification requirements.
In addition to $179.200, the individual specification requirements are as follows:
Minimum
DOT
Specification' Insulation
Bursting
thickness
plate
Test
References
pressure
Bottom Bottom (179.201
pressure (psig)
(inches)
(psig)
outlet washout +**)
111A60ALW1
Optional
240
60 Optional Optional 6(a).
111A60ALW2
Optional
240
60 NO
Optional.
111A60W1
Optional
240
16
60 Optional Optional 6(a).
111A60W2
Optional
240
60 No
Optional.
111A60W5
Optional
240
¾16|
60 NO
NO
3, 6(b).
111A60W6
Optional
240
16
60 Optional Optional 4, 5, 6(a), 6(c).
111A60W7
Optional
240
60 No
No
4, 5, 6(a).
111A100ALW1 Optional
500
100 Optional Optional 6(a).
111A100ALW2 Optional
500
100 No
Optional.
111A100W1
Optional
500
16
100 Optional Optional 6(a).
111A100W2
Optional
500
16
100 No
Optional.
111A100W3
Yes
500
100 Optional Optional 6(a).
111A100W4
Yes (see
500
179.201-11)
716/
100 NO
No
6(a), 8, 10.
111A100W5
Optional
500
"16
100 No
No
3.
111A100W6
Optional
500
16
100 Optional Optional |4, 5, 6(a) and
111A100W7
Optional
6(C).
500
100 NO
No
4, 5, 6(c).
'Tanks marked "ALW" are constructed from aluminum alloy plate; "AN" nickel plate; "CW," "DW," "EW."
"W6," and "W7" high alloy steel or manganese-molybdenum steel plate; and those marked "BW" or "W5" must
have an interior lining that conforms to 5179.201-3.
[Amdt. 179-52, 61 FR 28680, June 5, 1996, as amended by 66 FR 45390, Aug. 28, 2001; 68 FR 48571, Aug. 14, 2003]

<<<PAGE 7>>>

(f) Thickness tests. (1) The tank car owner must ensure that each tank car facility measures the thickness
of the tank car shell, heads, sumps, protective housing (i.e., domes), and nozzles on each tank car by using a
device capable of accurately measuring the thickness to within ‡0.05 mm (#0.002 inch).
(2) The tank car owner must ensure that each tank car has a thickness test measurement:
(i) At the time of an internal coating or lining application or replacement, or
(ii) At least once every ten (10) years for a tank that does not have an internal coating or lining. or
(il) At least once every five (5) years for a tank that does not have an internal coating or lining when:
(A) The tank is used to transport a material that is corrosive or reactive to the tank (see Appendix D of this
part) or service equipment as defined $180.503, and
(B) The remaining shell and head thickness is tested and determined to be at or below line C in Figure A
of this paragraph.
Eigure A
Tank and Shell Thickness Qualification Frequencies
Additional thickness
10 year inspection interval
5 year inspection interval
F
A E
Localized reductions only
View or download PDF
Where:
A. As-built tank shell or head thickness with additional thickness
B. Required minimum tank shell or head thickness after forming per part 179.
C. Inspection frequency adjustment point (design minimum shell or head thickness, minus ½ of the table value in paragraph (g)
of this section).
D. Condemning limit for general corrosion (required minimum shell or head thickness, minus the value in paragraph (g) of this
section).
E. Condemning limit for localized corrosion (required minimum shell or head thickness, minus the table value in paragraph (g)
of this section, minus 1.58 mm (16 inch)). See Note 1 in paragraph (g) of this section for diameter limitations and
minimum separation distances.
F. Allowable shell or head thickness reduction (table value in paragraph (g) of this section).
G. Additional thickness reduction for localized areas in paragraph (g) of this section.

<<<PAGE 8>>>

2.5 Requirements for DOT/TC Tank Cars Weighing Over 263,000 Ib GRL
2.5.1 All Class DOT/TC Tank Cars
the gross weight exceeds 263,000 lb.
Paragraph 2.5 applies to all Class DOT and TC tank cars ordered after December 31, 2003, when
2.5.1.1 Cars must comply with all requirements of the Office Manual of the AAR Interchange
Rules, latest version.
2.5.1.1.1 Cars must be in conformance with the truck requirements located in MSRP
Standard S-286 as required in the Office Manual of the AÅR Interchange Rules, Rule 88.
2.5.1.2 Shippers are reminded that regulations limit the gross weight of Class DOT/TC tank cars
to 263,000 Ib and that a federal exemption is required to operate these cars at heavier weights.
2.5.1.3 In addition to the design loads described in MSRP S-286, all REPOS loading, including
1.09 above the loading used for 263,000 Ib cars.
orizontal and vertical coupler loads, used for fatigue calculations must be increased by a factor of
and must have a "life-cycle" maintenance plan for cars. This must identify inspection items,
2.5.1.4 Car owner must identify appropriate areas of inspection for fatigue, corrosion, wear, etc.,
IMPLEMENTED 08/2018
inspection methods, acceptance criteria, and inspection frequencies. The car owner or designee
must have written procedures that ensure that work performed on cars conforms to federal and
AAR requirements.
2.5.1.5 New cars may not be equipped with reconditioned truck components.
over 263,000 Ib are not authorized.
2.5.1.6 Class DOT/TC cars with tanks constructed of aluminum or nickel plate with gross weight
2.5.2 Class DOT/TC-111 Nonpressure Tank Cars
Appendix E, paragraph 9.2.
2.5.2.1 Class DOT/TC-111 cars must be equipped with top fittings protection in accordance with
where the applicant can demonstrate that a non-reclosing device affords an equivalent level of
2.5.2.2 Class DOT/TC-111 cars must be equipped with reclosing pressure relief devices, except
safety.
criteria:
2.5.2.3 Class DOT/TC-111 cars with carbon steel tanks must meet one of the following minimum
• Tanks are constructed of normalized 'TC128 steel at least 7/16 in. thick and equipped with
steel jackets and 1/2 in. thick steel jacket heads.
• Tanks are constructed of normalized TC128 steel at least 1/2 in. thick and equipped with
1/2 in. thick steel half-head shields.
• Tanks are constructed of normalized ASTM A516 steel at least 1/2 in. thick and equipped
with steel jackets and 1/2 in. thick steel jacket heads.
• Tanks are constructed of normalized ASTM A516 steel at least 5/8 in. thick and equipped
with 1/2 in. thick steel half-head shields.

<<<PAGE 9>>>

Please & Thank You,
Keenan Moore
Fleet Management Specialist
Keenan@TCIXRail.com
Office: (903) 653-4077
Cell: (903) 241-4079
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