# Union Pacific Railroad Co.—Abandonment Exemption—in Jefferson County, Wis.
On September 24, 2025, Union Pacific Railroad Co. (UP), a Class I rail carrier, filed a petition under 49 U.S.C. 10502 for an exemption from the prior approval requirements of 49 U.S.C. 10903 to abandon an approximately 0.88-mile rail line known as the Jefferson Junction Lead between milepost 49.12 at the Clyman Subdivision and milepost 50, near the city of Jefferson, all of which is located in Jefferson County, Wis. (the Line). The Line traverses U.S. Postal Service Zip Codes 53549 and 53038, and the verified notice identifies no stations on the Line.
UP states that it seeks to abandon the Line and sell the track to Aztalan Bio, LLC (Aztalan), the only shipper on the Line, which will remove and reconfigure the track adjacent to its facility. (Pet. 2.) According to UP, the reconfigured track will connect to the Clyman Subdivision, where UP will provide rail service to Aztalan, and use of the Line will be limited to Aztalan's movement of railcars at its facilities; storage, loading and unloading operations; and receipt and delivery of rail cars to UP. ( *Id.* at 3.) UP states that no other industries are located on the Line and that no shippers have requested to locate on the Line. *Id.*
According to UP, based on information in its possession, the Line does not contain federally granted rights-of-way. ( *Id.* at 3.) UP further states that any documentation in UP's possession will be made available promptly to those requesting it. ( *Id.* )
The interest of railroad employees will be protected by the conditions set forth in *Oregon Short Line Railroad—Abandonment Portion Goshen Branch Between Firth & Ammon, in Bingham & Bonneville Counties, Idaho,* 360 I.C.C. 91 (1979).
By issuing this notice, [^1] the Board is instituting an exemption proceeding pursuant to 49 U.S.C. 10502(b). A final decision will be issued by January 12, 2026.
[^1] Due to the shutdown of the Federal government due to a lapse in appropriations from October 1, 2025, through November 12, 2025, the Board was not able to timely publish notice of the petition. *See* 49 CFR 1152.27(b)(2)(i).
Any offer of financial assistance (OFA) under 49 CFR 1152.27(b)(2) will be due no later than 120 days after the filing of the petition for exemption, or 10 days after service of a decision granting the petition for exemption, whichever occurs sooner. Persons interested in submitting an OFA must first file a formal expression of intent to file an offer by December 1, 2025, indicating the type of financial assistance they wish to provide ( *i.e.,* subsidy or purchase) and demonstrating that they are preliminarily financially responsible. *See* 49 CFR 1152.27(c)(1)(i).
The Line may be suitable for other public use, including interim trail use. Any request for a public use condition under 49 CFR 1152.28 or for interim trail use/railbanking under 49 CFR 1152.29 will be due no later than December 11, 2025. [^2]
[^2] Filing fees for OFAs and trail use requests can be found at 49 CFR 1002.2(f)(25) and (27), respectively.
All pleadings, referring to Docket No. AB 33 (Sub-No. 354X), must be filed with the Surface Transportation Board either via e-filing on the Board's website or in writing addressed to 395 E Street SW, Washington, DC 20423-0001. In addition, a copy of each pleading must be served on UP's representative, Christine Neuharth, Senior Counsel, Union Pacific Railroad Company, 1400 Douglas St. MS #1580, Omaha, NE 68179. Replies to the petition are due on or before December 11, 2025.
Persons seeking further information concerning abandonment procedures may contact the Board's Office of Public Assistance, Governmental Affairs, and Compliance at (202) 245-0238 or refer to the full abandonment regulations at 49 CFR part 1152. Questions concerning environmental issues may be directed to the Board's Office of Environmental Analysis (OEA) at (202) 245-0294. If you require an accommodation under the Americans with Disabilities Act, please call (202) 245-0245.
OEA will prepare an environmental assessment (EA) (or environmental impact statement (EIS), if necessary), which will be served upon all parties of record and upon any other agencies or persons who comment during its preparation. Other interested persons may contact OEA to obtain a copy of the EA (or EIS). EAs in abandonment proceedings normally will be made available within 60 days of the filing of the petition. The deadline for submission of comments on the EA generally will be within 30 days of its service.
Board decisions and notices are available at *www.stb.gov* .
By the Board, Anika S. Cooper, Chief Counsel, Office of Chief Counsel.
Decided: November 18, 2025.
Stefan Rice,
Clearance Clerk.