[Federal Register Volume 83, Number 145 (Friday, July 27, 2018)]
[Notices]
[Pages 35699-35702]
[FR Doc No: 2018-16022]

=======================================================================
-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Railroad Administration

[Docket No. FRA-2017-0074, Notice No. 2; Safety Advisory 2018-01]

Addressing Electrode-Induced Rail Pitting From Pressure Electric
Welding

AGENCY: Federal Railroad Administration (FRA), Department of
Transportation (DOT).

ACTION: Notice of Safety Advisory.

-----------------------------------------------------------------------

SUMMARY: FRA is issuing Safety Advisory 2018-01 to remind railroads,
contractors, and the rail welding industry of the potential for
electrode-induced rail pitting and fatigue cracking during the pressure
electric rail welding process.

FOR FURTHER INFORMATION CONTACT: Mr. Matthew Brewer, Staff Director,
Rail Integrity Division, Office of Railroad Safety, FRA, 500 Broadway,
Suite 240, Vancouver, WA 98660, telephone<PHONE_NUMBER>; or Mr. Aaron
Moore, Trial Attorney, Office of Chief Counsel, FRA, 1200 New Jersey
Avenue SE, Washington, DC 20590, telephone<PHONE_NUMBER>.

SUPPLEMENTARY INFORMATION: On August 16, 2017, FRA published a notice
of a draft safety advisory in the Federal Register to address
electrode-induced rail pitting from pressure electric welding and
seeking comment on the issue. 82 FR 38989. FRA noted its investigation
and research into the issue demonstrated that improper electrode
contact to the rail during the welding process could result in
electrode-induced pitting that may lead to fatigue fracture and
ultimately rail failure. As a result, FRA's draft safety advisory
contained specific recommendations to help the industry prevent
electrode-induced pitting.
    FRA presented the information contained in the draft safety
advisory to its Railroad Safety Advisory Committee's (RSAC) Rail
Integrity Working Group. Subsequent RSAC discussions and comments
submitted by the Association of American Railroads (AAR) indicated that
the rail industry agrees with FRA's concern that stray arcing can
result in the formation of electrode pits and that fatigue cracking can
then develop from these electrode pits. AAR noted, however, that FRA's
draft safety advisory did not present any information to support a
finding that rail failures from electrode-induced rail pitting are a
wide-spread problem. Further, AAR noted that its member railroads
report they have seen no indications of a systemic problem involving
electrode pitting, and that railroads and welding companies have
procedures in place to prevent electrode pitting and remediate it when
it does occur. Accordingly, AAR asserted that FRA should not issue any
recommendations burdening the industry such as those included in the
draft safety advisory.
    After consideration of AAR's comments and input from RSAC
discussions, FRA agrees with AAR's position that, although stray arcing
during the pressure electric welding process can result in the
formation of electrode burns or pits on the web, head, or base of rail,
and that fatigue cracking can develop from those burns or pits,
railroads and welding companies have procedures in place addressing the
issue of electrode pitting. Accordingly, in issuing Safety Advisory
2018-01, FRA has not adopted the specific recommended actions listed in
its draft safety advisory and instead intends Safety Advisory 2018-01
to merely remind railroads, contractors, and the rail welding industry
to be diligent in complying with existing practices and procedures
designed to prevent electrode-induced pitting in rail and to mitigate
the pitting when it does occur.

Safety Advisory 2018-01

    Pressure electric welding is the process of using a hydraulically-
operated welding head that clamps around two opposing rail ends,
pressing an electrode on each rail, then hydraulically pulling the rail
ends together while arcing current through the electrodes into the
rails, causing them to essentially melt together to form a continuous
rail. Stray arcing during this process results in the formation of
electrode burns or pits on the web, head, or base of the rail.
Fractures in the rail may originate from the electrode pits because
they behave as stress raisers (also referred to as stress
concentrations). Fatigue cracks may develop at locations of stress
concentration. Once a fatigue crack initiates, the localized stress
encourages the growth of the crack, which may potentially lead to rail
failure. FRA believes electrode pitting may be a contributing factor,
if not the root cause, in some accidents involving rail web cracking.
    Figure 1 below shows a photograph of a rail with electrode pits in
the web. The location of these electrode pits, when they occur, is
typically four to eight inches on either side of the weld. Electrode-
induced pitting from pressure electric welding may also occur in the
head and base of the rail. It is unclear whether traditional ultrasonic
rail testing can consistently detect electrode-induced pitting.
    In 2016, FRA's Office of Railroad Safety requested technical
support from The National Transportation Systems Center (Volpe) to
study the fatigue and fracture behavior of rails with pitting from
electrodes used in welding. Volpe enlisted technical support from the
U.S. Army's Ben[eacute]t Laboratories (Ben[eacute]t) to conduct
forensic examination of three rail sections with electrode-induced
pitting in the web from the pressure electric welding process. FRA
obtained these rails from members of the railroad industry.
Ben[eacute]t's examination included fractography (the science of
studying fracture surfaces to identify the origin and causes of
fracture), metallography (the science of studying the microstructure of
metals to provide information concerning the properties and processing
history of metallic alloys), and testing to determine the chemical
composition and tensile mechanical properties of the rail steel.
Ben[eacute]t confirmed the electrode-induced web fatigue cracking is a
result of pitting caused by inadequate electrode-to-rail contact.
    Specifically, Ben[eacute]t's metallurgical analyses concluded the
cracking in the rail web originated from the pitting created by
inadequate electrode-to-rail contact during the pressure electric
welding process. The fractographic and metallographic examinations
revealed evidence of fatigue cracking originating from the pitting and
fast fracture once the fatigue crack reached a critical length. Figure
2 below shows three photographs of the fracture surface of a crack
found in one of the rails Ben[eacute]t examined. These photographs
support the metallurgical evidence indicative of three stages of
fatigue fracture: (1) Crack initiation or formation originating from
the pitting; (2) crack propagation or growth by metal fatigue; and (3)
final rupture or fast fracture. Figure 3 below shows photographs of the
microstructure near the electrode pits in each examined rail, providing
further evidence the cracking originated from the pitting created by
improper electrode contact during welding.
    The results from the metallurgical analysis also suggested
premature and sudden rail failure may result from high wheel-impact
load (e.g., flat wheel), especially in cold-weather environments when
the longitudinal rail force is tensile. Results from the chemical
analysis and mechanical testing indicated the chemistry and mechanical
properties of the rails selected for evaluation were within
specifications the American Railway Engineering and Maintenance-of-Way

Association (AREMA) published, except for the hardness measurements in
one rail, which were slightly lower than the AREMA minimum. Hardness is
a measure of the resistance of a material to surface indentation
produced by a carbide indenter applied at a given load for a given
length of time. The lower hardness in that rail, manufactured in the
1950s, may be attributed to lower concentrations (compared to the other
two rails) of alloying elements, specifically carbon, silicon, and
chromium, which were still within AREMA tolerances. Testing of the
chemistry and the mechanical properties revealed all three rails were
made from standard quality steel containing no other defects except the
electrode-induced pitting.
    FRA recognizes that the industry already has practices and
procedures in place to avoid electrode pitting during the pressure
electric welding process. Therefore, FRA is issuing Safety Advisory
2018-01 to remind railroads, railroad employees, railroad contractors,
and welding companies and their employees of the importance of
complying with those procedures to prevent electrode pitting and,
ultimately, to prevent rail failures. (FRA has posted a copy of this
notice on its public website, www.fra.dot.gov, where you may view the
figures below in their full resolution.)
 BILLING CODE 4910-06-P

[GRAPHIC] [TIFF OMITTED] TN27JY18.329

Ronald Louis Batory,
Administrator.
[FR Doc. 2018-16022 Filed 7-26-18; 8:45 am]
 BILLING CODE 4910-06-C


[Federal Register Volume 86, Number 54 (Tuesday, March 23, 2021)]
[Notices]
[Pages 15476-15477]
[FR Doc No: 2021-05380]

=======================================================================
-----------------------------------------------------------------------

ENVIRONMENTAL PROTECTION AGENCY

[EPA-HQ-ORD-2020-0564; FRL 10020-77-ORD]

Multiple-Path Particle Dosimetry (MPPD) Model Software (MPPD EPA
2021 v.1.01) With Technical Support Documentation and User's Guide
(External Review Draft)

AGENCY: Environmental Protection Agency (EPA).

ACTION: Notice; request for public comment.

-----------------------------------------------------------------------

SUMMARY: The Environmental Protection Agency (EPA) is announcing an
external expert peer review and public comment for the EPA Multiple-
Path Particle Dosimetry (MPPD) Model Software (MPPD EPA 2021 v. 1.01)
and its associated ``Technical Support Documentation and User's Guide
(External Review Draft)'' ([EPA/600/R-20/406]). The document was
prepared by the Center for Public Health and Environmental Assessment
(CPHEA) within EPA's Office of Research and Development (ORD), with
contributions from Applied Research Associates, Inc., and Fred J.
Miller, LLC. EPA is releasing this draft model software version and
associated document to seek review by external experts and the public.
This external review draft document and model software (MPPD EPA 2021
v. 1.01) are not final and do not represent, and should not be
construed to represent, any final Agency policy or views. When revising
the document and the model software, EPA will consider any peer or
public comments submitted during the public comment period specified in
this document.

DATES: The 30-day public comment period begins March 23, 2021 and ends
April 22, 2021. Comments must be received on or before April 22, 2021.

ADDRESSES: The EPA Multiple-Path Particle Dosimetry (MPPD) Model
Software (MPPD EPA 2021 v. 1.01) and its associated ``Technical Support
Documentation and User's Guide'' (External Review Draft)'' will be
available from the contractor managing the external peer review,
Eastern Research Group, Inc. (ERG). To obtain a copy of the external
review draft or the associated MPPD software (EPA 2021 v. 1.01),
contact ERG at email<EMAIL_ADDRESS>with the Subject line: MPPD
EPA 2021 Peer Review; Phone:<PHONE_NUMBER>.

FOR FURTHER INFORMATION CONTACT: For information on the public comment
period, contact the ORD Docket at the EPA Headquarters Docket Center;

phone:<PHONE_NUMBER>; fax:<PHONE_NUMBER>; or email<EMAIL_ADDRESS>
For technical information, contact Annie M. Jarabek; phone: 919-637-
6016; or email<EMAIL_ADDRESS>
SUPPLEMENTARY INFORMATION:

I. Information About the Document and MPPD Model Software

    The EPA is undertaking an external peer review of an EPA version of
the Multiple-Path Particle Dosimetry (MPPD) model (MPPD EPA 2021 v.
1.01) and its software, together with an EPA Technical Support
Documentation and User's Guide. The EPA introduced formal dosimetry
modeling into its derivation procedures for risk assessment of inhaled
materials with its 1994 document entitled ``Methods for Derivation of
Inhalation Reference Concentrations (RfCs) and Application of
Inhalation Dosimetry'' (US EPA, 1994). These methods relied upon the
Regional Deposited Dose Ratio (RDDR) model and underwent two expert
technical panel and two expert Science Advisory Board (SAB) reviews
prior to finalization. The dosimetry adjustments were also subsequently
incorporated into the Agency's guidelines for carcinogen risk
assessment (US EPA, 2005).
    The EPA RDDR model was an empirical model fit to a unique set of
experimental data from inhalation studies across five laboratory animal
species commonly used in testing for regulatory risk assessment as well
as for humans. The model provided predictions of inhaled deposited dose
in various regions of the respiratory tract, including the
extrathoracic (ET), tracheobronchial (TB), pulmonary (PU), thoracic (TB
+ PU) or total respiratory tract (TOTAL).
    However, since 1994, mechanistic modeling of inhalation dosimetry
for particles has matured. The MPPD model and its software include many
modernized features, with some dose metric predictions now based on
mechanistic descriptions instead of empirical fitting, the ability to
address a wider range of particle size, providing prediction of
retained mass for some species, and including some different test
species.
    The EPA is convening this external peer review to evaluate the MPPD
model. The model results provide dosimetry adjustment of inhalation
exposures for the following purposes: Interspecies extrapolation,
evaluation of intra-human variability, informing experimental design,
and in vitro to in vivo (IVIVE) extrapolation.
    The EPA Multiple-Path Particle Dosimetry (MPPD) Model Software
(MPPD EPA 2021 v. 1.01) and its associated ``Technical Support
Documentation and User's Guide (External Review Draft)'' will be
discussed at a virtual external expert peer review meeting, which will
be open to the public. In addition to the opportunity to submit written
comments during the public comment period announced in this notice, the
public will have an opportunity to make brief oral comments during the
virtual expert peer panel meeting. For more information about the peer
review meeting, including information about how to register, please
visit: https://projects.erg.com/conferences/peerreview/register-mppd.html.

II. How To Submit Technical Comments to the Docket at
www.regulations.gov

    Out of an abundance of caution for members of the public and our
staff, the EPA Docket Center and Reading Room are closed to the public,
with appointment only, to reduce the risk of transmitting COVID-19. Our
Docket Center staff will continue to provide remote customer service
via email, phone, and webform. We encourage the public to submit
comments via the web at https://www.regulations.gov/ or via email at
<EMAIL_ADDRESS>as there may be a delay in processing mail and
faxes. Hand deliveries and couriers may be received by scheduled
appointment only. For further information on EPA Docket Center services
and the current status, please visit https://www.epa.gov/dockets.
    Submit your materials identified by Docket ID No. EPA-HQ-ORD-2020-
0564 by one of the following methods:
     www.regulations.gov: Follow the online instructions for
submitting comments.
     Email<EMAIL_ADDRESS>     Fax:<PHONE_NUMBER>.
     Mail: Office of Research and Development (ORD) Docket
(Mail Code: 28221T), U.S. Environmental Protection Agency, 1200
Pennsylvania Ave. NW, Washington, DC 20460. The phone number is 202-
566-1752.
     Hand Delivery: The ORD Docket is located in EPA's
Headquarters Docket Center, Room 3334 EPA West Building, 1301
Constitution Ave. NW, Washington, DC. If you provide materials by mail
or hand delivery, please submit three copies of these materials. For
attachments, provide an index, number pages consecutively with the
materials, and submit an unbound original and three copies.
    Instructions: Direct your comments to Docket ID No. EPA-HQ-ORD-
2020-0564. Please ensure that your comments are submitted within the
specified comment period. Comments received after the closing date will
be marked ``late,'' and may only be considered if time permits. It is
EPA's policy to include all materials it receives in the public docket
without change and to make the materials available online at
www.regulations.gov, including any personal information provided,
unless materials include information claimed to be Confidential
Business Information (CBI) or other information whose disclosure is
restricted by statute. Do not submit information that you consider to
be CBI or otherwise protected through www.regulations.gov or email. The
www.regulations.gov website is an ``anonymous access'' system, which
means EPA will not know your identity or contact information unless you
provide it in the body of your comment. If you send an email directly
to EPA without going through www.regulations.gov, your email address
will be automatically captured and included as part of the materials
that are placed in the public docket and made available on the
internet. If you submit electronic materials, EPA recommends that you
include your name and other contact information in the body of your
materials and with any disk or CD-ROM you submit. If EPA cannot read
your materials due to technical difficulties and cannot contact you for
clarification, EPA may not be able to consider the materials you
submit. Electronic files should avoid the use of special characters,
any form of encryption, and be free of any defects or viruses. For
additional information about EPA's public docket, visit EPA's Docket
Center homepage at www.epa.gov/epahome/dockets.htm.
    Docket: Documents in the docket are listed in the
www.regulations.gov index. Although listed in the index, some
information is not publicly available, e.g., CBI or other information
whose disclosure is restricted by statute. Certain other materials,
such as copyrighted material, are publicly available only in hard copy.
Publicly available docket materials are available either electronically
in www.regulations.gov or in hard copy at the ORD Docket in EPA's
Headquarters Docket Center.

    Authority: Pub. L. 94-475; Environmental Research, Development,
and Demonstration Authorization Act of 1976.

    Dated: February 18, 2021.
Vanessa Holt,
Acting Director, Center for Public Health and Environmental Assessment
(CPHEA).
[FR Doc. 2021-05380 Filed 3-22-21; 8:45 am]
BILLING CODE 6560-50-P