Proposed Rule2025-12159
Expanding Certain Locomotive Wheel Set Diameter Variations
Primary source
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Published
July 1, 2025
Issuing agencies
Transportation DepartmentFederal Railroad Administration
Abstract
FRA proposes to amend its locomotive safety regulations to expand the maximum permitted variation in diameter for locomotive wheel sets using alternating current technology, in response to a Class I railroad's May 2019 petition for rulemaking and innovations in traction motor control.
Full Text
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<title>Federal Register, Volume 90 Issue 124 (Tuesday, July 1, 2025)</title>
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[Federal Register Volume 90, Number 124 (Tuesday, July 1, 2025)]
[Proposed Rules]
[Pages 28658-28660]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2025-12159]
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DEPARTMENT OF TRANSPORTATION
Federal Railroad Administration
49 CFR Part 229
[Docket No. FRA-2025-0126]
RIN 2130-AD50
Expanding Certain Locomotive Wheel Set Diameter Variations
AGENCY: Federal Railroad Administration (FRA), Department of
Transportation (DOT).
ACTION: Notice of proposed rulemaking (NPRM).
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SUMMARY: FRA proposes to amend its locomotive safety regulations to
expand the maximum permitted variation in diameter for locomotive wheel
sets using alternating current technology, in response to a Class I
railroad's May 2019 petition for rulemaking and innovations in traction
motor control.
DATES: Comments on the proposed rule must be received by September 2,
2025. FRA may consider comments received after that date, but only to
the extent practicable.
ADDRESSES:
Comments: Comments related to Docket No. FRA-2025-0126 may be
submitted by going to <a href="https://www.regulations.gov">https://www.regulations.gov</a> and following the
online instructions for submitting comments.
Instructions: All submissions must include the agency name, docket
number (FRA-2025-0126), and Regulatory Identification Number (RIN) for
this rulemaking (2130-AD50). All comments received will be posted
without change to <a href="https://www.regulations.gov">https://www.regulations.gov</a>; this includes any
personal information. Please see the Privacy Act heading in the
SUPPLEMENTARY INFORMATION section of this document for Privacy Act
information related to any submitted comments or materials.
Docket: For access to the docket to read background documents or
comments received, go to <a href="https://www.regulations.gov">https://www.regulations.gov</a> and follow the
online instructions for accessing the docket.
FOR FURTHER INFORMATION CONTACT: Gary Fairbanks, Staff Director, Motive
Power & Equipment Division, Federal Railroad Administration, telephone:
(202) 230-9594, email: <a href="/cdn-cgi/l/email-protection#761117040f5810171f041417181d053612190258111900"><span class="__cf_email__" data-cfemail="caadabb8b3e4acaba3b8a8aba4a1b98aaea5bee4ada5bc">[email protected]</span></a>; or Michael Masci,
Attorney Adviser, Federal Railroad Administration, telephone: (202)
302-7177, email: <a href="/cdn-cgi/l/email-protection#e5888c868d848089cb888496868ca5818a91cb828a93"><span class="__cf_email__" data-cfemail="076a6e646f66626b296a6674646e4763687329606871">[email protected]</span></a>.
SUPPLEMENTARY INFORMATION:
I. Background
Consistent with the deregulatory agenda of President Donald J.
Trump and Secretary of Transportation Sean P. Duffy, which seeks to
unleash America's economic prosperity without compromising
transportation safety, FRA is reviewing its regulatory requirements in
parts 200 through 299 of title 49, Code of Federal Regulations (CFR).
Under 49 CFR part 229, Railroad Locomotive Safety Standards, FRA
prescribes minimum Federal safety standards for all locomotives except
those propelled by steam power. Some of the requirements contained in
part 229 could be updated to reduce burdens, make technical or
conforming changes, or otherwise adjust to advancing technology without
any adverse effect on railroad safety. Please review the Section-by-
Section Analysis below for the relevant information related to each
proposed change.
II. Section-by-Section Analysis
Section 229.73 Wheel Sets
FRA proposes to amend paragraph (b) of this section to expand the
maximum permitted variation in diameter for locomotive wheel sets using
alternating current (AC) technology. In May 2019, Union Pacific
Railroad submitted a petition for rulemaking under 49 CFR part 209 on
the basis that ``[n]ew technology with individual axle control
developed and placed in service after 1980 provides the basis for
change which will result in better customer service through a reduction
of locomotive out of service time and increased wheel life without
impacting safety.'' \1\
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\1\ UP's petition for rulemaking is available in Docket No. FRA-
2025-0126 on <a href="https://www.regulations.gov">https://www.regulations.gov</a>.
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Generally, excessive wheel size variation is a safety concern due
to the potential impact on wheel slip and truck dynamics. For older
locomotives equipped with direct current (DC) traction motors,
excessive wheel size variation causes current imbalance and triggers
wheel slip corrections, including unnecessary sanding, removing
tractive effort, and removing power. These corrections can have adverse
effects on the equipment and efficiency of operations but are necessary
to prevent more serious safety hazards like damage to the rail. Newer
locomotives equipped with AC traction motors utilize single axle
control technology to apply voltage and control current more precisely
to each wheel set based on operating conditions. As such, the AC
traction motors function as an independent wheel slip correction system
that do not use wheel size variation as a trigger for correction.
Despite the improvements to prevent wheel slip, wheel sets on
locomotives equipped with AC traction motors still need to minimize
wheel size variation to help maintain proper truck dynamics. Excessive
wheel size variation can decrease the effectiveness of weight
distribution from corresponding trucks, and the trucks' inability to
help absorb the impact of a shifting load could lead to a derailment.
Existing paragraph (b) of Sec. 229.73 specifies that the maximum
variation in the diameter between any two wheel sets on different
trucks on a locomotive that has three-powered-axle trucks may not
exceed 1\1/4\ inches. FRA proposes to separate the existing requirement
in current paragraph (b) into new paragraphs (b)(1)(i) and (b)(1)(ii),
generally continuing the current 1\1/4\ inch maximum variation for
wheel sets on older locomotives equipped with DC traction motors. FRA
proposes to add a new paragraph (b)(2)(i), generally allowing a 1\1/2\
inch maximum variation for wheel sets on newer locomotives equipped
with AC traction motors that utilize single axle control. Proposed new
paragraph (b)(2)(ii) would eliminate the wheel set variation
requirement of this section for wheel sets on non-powered axles on
locomotives equipped with AC traction motors that utilize single axle
control because FRA does not expect wheel variation to have a
significant impact on truck dynamics in that case. FRA expects this
proposal would better
[[Page 28659]]
accommodate new technology and maintain current levels of safety.
III. Regulatory Impact and Notices
A. Executive Order (E.O.) 12866 (Regulatory Planning and Review) and
DOT Regulatory Policies and Procedures
FRA has considered the impact of this proposed rule under E.O.
12866, Regulatory Planning and Review (58 FR 51735, Oct. 4, 1993), and
DOT Order 2100.6B, Policies and Procedures for Rulemaking (Mar. 10,
2025). The Office of Information and Regulatory Affairs within the
Office of Management and Budget (OMB) determined that this NPRM is not
a significant regulatory action under section 3(f) of E.O. 12866. This
proposed rule would amend FRA's locomotive safety regulations to expand
the maximum permitted variation in diameter for wheel sets using
alternating current technology.
FRA expects that this proposed rule would result in cost savings to
the industry as it would increase a maximum threshold for certain
locomotives under 49 CFR 229.73(b) due to innovations in traction motor
control. This would, in turn, result in a reduction of locomotive out-
of-service time and increased wheel life without impacting safety. The
increased allowable variation would help reduce the regulatory burden
on the railroad industry while maintaining proper truck dynamics.
B. E.O. 14192 (Unleashing Prosperity Through Deregulation)
E.O. 14192, Unleashing Prosperity Through Deregulation (90 FR 9065,
Jan. 31, 2025), requires that for ``each new [E.O. 14192 regulatory
action] issued, at least ten prior regulations be identified for
elimination.'' \2\ Implementation guidance for E.O. 14192 issued by OMB
(Memorandum M-25-20, Mar. 26, 2025) defines two different types of E.O.
14192 actions: an E.O. 14192 deregulatory action, and an E.O. 14192
regulatory action.\3\
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\2\ Executive Office of the President. Executive Order 14192 of
January 31, 2025. Unleashing Prosperity Through Deregulation. 90 FR
9065-9067 (Feb. 6, 2025).
\3\ Executive Office of the President. Office of Management and
Budget. Guidance Implementing Section 3 of Executive Order 14192,
Titled ``Unleashing Prosperity Through Deregulation.'' Memorandum M-
25-20. Mar. 26, 2025.
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An E.O. 14192 deregulatory action is defined as ``an action that
has been finalized and has total costs less than zero.'' This proposed
rulemaking is expected to have total costs less than zero, and
therefore it would be considered an E.O. 14192 deregulatory action upon
issuance of a final rule. While FRA affirms that each amendment
proposed in this NPRM has a cost that is negligible or ``less than
zero'' consistent with E.O. 14192, FRA requests comment on the extent
of the cost savings for the changes proposed in this NPRM.
C. Regulatory Flexibility Act and E.O. 13272
The Regulatory Flexibility Act (5 U.S.C. 601 et seq.), as amended
by the Small Business Regulatory Enforcement Fairness Act of 1996,\4\
requires Federal agencies to consider the effects of the regulatory
action on small business and other small entities and to minimize any
significant economic impact. Accordingly, DOT policy requires an
analysis of the impact of all regulations on small entities, and
mandates that agencies strive to lessen any adverse effects on these
businesses. The term small entities comprises small businesses and not-
for-profit organizations that are independently owned and operated and
are not dominant in their fields, and governmental jurisdictions with
populations of less than 50,000 (5 U.S.C. 601(6)).
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\4\ Public Law 104-121, 110 Stat. 857 (Mar. 29, 1996).
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No regulatory flexibility analysis is required, however, if the
head of an Agency or an appropriate designee certifies that the rule
would not have a significant economic impact on a substantial number of
small entities. This proposed rule would not preclude small entities
from continuing existing practices that comply with part 229; it merely
offers flexibilities that could result in cost savings if a small
entity or other regulated entity chooses to utilize those
flexibilities. By extending this regulatory relief, many regulated
entities, including small entities, would experience a cost savings.
Consequently, FRA certifies that the proposed action would not have a
significant economic impact on a substantial number of small entities.
In accordance with section 213(a) of the Small Business Regulatory
Enforcement Fairness Act of 1996 (Pub. L. 104-121, 110 Stat. 857), FRA
wants to assist small entities in understanding this proposed rule so
they can better evaluate its effects on themselves and participate in
the rulemaking initiative. If the proposed rule would affect your small
business, organization, or governmental jurisdiction and you have
questions concerning its provisions or options for compliance, please
consult the person listed under FOR FURTHER INFORMATION CONTACT.
D. Paperwork Reduction Act
This proposed rule offers regulatory flexibilities, and it contains
no new information collection requirements under the Paperwork
Reduction Act of 1995 (44 U.S.C. 3501-3520).
E. Environmental Assessment
FRA has analyzed this rule for the purposes of the National
Environmental Policy Act of 1969 (NEPA). In accordance with 42 U.S.C.
4336 and DOT NEPA Order 5610.1C, FRA has determined that this rule is
categorically excluded pursuant to 23 CFR 771.118(c)(4), ``[p]lanning
and administrative activities that do not involve or lead directly to
construction, such as: [p]romulgation of rules, regulations, and
directives.'' This rulemaking is not anticipated to result in any
environmental impacts, and there are no unusual or extraordinary
circumstances present in connection with this rulemaking.
Pursuant to Section 106 of the National Historic Preservation Act
and its implementing regulations, FRA has determined this undertaking
has no potential to affect historic properties. FRA has also determined
that this rulemaking does not approve a project resulting in a use of a
resource protected by Section 4(f).
F. Federalism Implications
This proposed rule would not have a substantial effect on the
States, on the relationship between the national government and the
States, or on the distribution of power and responsibilities among the
various levels of government. Thus, in accordance with E.O. 13132,
``Federalism'' (64 FR 43255, Aug. 10, 1999), preparation of a
Federalism Assessment is not warranted.
G. Unfunded Mandates Reform Act of 1995
This proposed rule would not result in the expenditure, in the
aggregate, of $100,000,000 or more, adjusted for inflation, in any one
year by State, local, or Indian Tribal governments, or the private
sector. Thus, consistent with section 202 of the Unfunded Mandates
Reform Act of 1995 (Pub. L. 104-4, 2 U.S.C. 1532), FRA is not required
to prepare a written statement detailing the effect of such an
expenditure.
H. Energy Impact
E.O. 13211, Actions Concerning Regulations that Significantly
Affect Energy Supply, Distribution, or Use, 66 FR 28355 (May 22, 2001),
requires Federal agencies to prepare a Statement of Energy Effects for
any ``significant
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energy action.'' FRA has evaluated this proposed rule in accordance
with E.O. 13211 and determined that this proposed rule is not a
``significant energy action'' within the meaning of E.O. 13211.
I. E.O. 13175 (Tribal Consultation)
FRA has evaluated this proposed rule in accordance with the
principles and criteria contained in E.O. 13175, Consultation and
Coordination with Indian Tribal Governments (Nov. 6, 2000). The
proposed rule would not have a substantial direct effect on one or more
Indian tribes, would not impose substantial direct compliance costs on
Indian tribal governments, and would not preempt tribal laws.
Therefore, the funding and consultation requirements of E.O. 13175 do
not apply, and a tribal summary impact statement is not required.
J. International Trade Impact Assessment
The Trade Agreement Act of 1979 \5\ prohibits Federal agencies from
engaging in any standards or related activities that create unnecessary
obstacles to the foreign commerce of the United States. Legitimate
domestic objectives, such as safety, are not considered unnecessary
obstacles. The statute also requires consideration of international
standards and, where appropriate, that they be the basis for U.S.
standards. This rulemaking is purely domestic in nature and is not
expected to affect trade opportunities for U.S. firms doing business
overseas or for foreign firms doing business in the United States.
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\5\ 19 U.S.C. ch. 13.
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K. Privacy Act Statement
In accordance with 5 U.S.C. 553(c), DOT solicits comments from the
public to better inform its rulemaking process. DOT posts these
comments, without edit, to <a href="https://www.regulations.gov">https://www.regulations.gov</a>, as described in
the system of records notice, DOT/ALL-14 FDMS, accessible through
<a href="http://www.transportation.gov/privacy">www.transportation.gov/privacy</a>. To facilitate comment tracking and
response, we encourage commenters to provide their name, or the name of
their organization; however, submission of names is completely
optional. Whether or not commenters identify themselves, all timely
comments will be fully considered. If you wish to provide comments
containing proprietary or confidential information, please contact the
agency for alternate submission instructions.
L. Rulemaking Summary
As required by 5 U.S.C. 553(b)(4), a summary of this rule can be
found at <a href="https://www.regulations.gov">https://www.regulations.gov</a>, Docket No. FRA-2025-0126, in the
SUMMARY section of this proposed rule.
List of Subjects in 49 CFR Part 229
Penalties, Railroad safety, Reporting and recordkeeping
requirements.
The Proposed Rule
For the reasons discussed in the preamble, FRA proposes to amend
part 229 of chapter II, subtitle B of title 49, Code of Federal
Regulations as follows:
PART 229--RAILROAD LOCOMOTIVE SAFETY STANDARDS
0
1. The authority citation for part 229 continues to read as follows:
Authority: 49 U.S.C. 20103, 20107, 20133, 20137-38, 20143,
20168, 20701-03, 21301-02, 21304; 28 U.S.C. 2461 note; and 49 CFR
1.89.
0
2. Amend Sec. 229.73 by revising paragraph (b) to read as follows:
Sec. 229.73 Wheel sets.
* * * * *
(b) The maximum variation in the diameter between any two wheel
sets (the average diameter of the two wheels on an axle) shall not
exceed the following:
(1) For wheel sets on locomotives equipped with direct current
traction motors:
(i) Within the same three-powered-axle truck, \3/4\ inch, except
that when shims are used at the journal box springs to compensate for
wheel diameter variation, the maximum variation may not exceed 1\1/4\
inches.
(ii) On different trucks on a locomotive that has three-powered-
axle trucks, 1\1/4\ inches.
(2) For wheel sets on locomotives equipped with alternating current
traction motors that utilize individual truck or single axle control
technology:
(i) Powered axles, 1\1/2\ inches, with or without shims.
(ii) Non-powered axles in the middle of two powered axles, the
restriction of 1\1/2\ inches, with or without shims, does not apply.
* * * * *
Issued in Washington, DC.
Kyle D. Fields,
Chief Counsel.
[FR Doc. 2025-12159 Filed 6-27-25; 4:15 pm]
BILLING CODE 4910-06-P
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