​This information is preliminary and subject to change.
Updated 29 October, 2025​​

On September 20, 2025, about 11:07 p.m. local time, Kinder Morgan Inc.’s supervisory control and data acquisition (SCADA) system detected a pressure drop on a 22-inch interstate natural gas transmission pipeline that crosses the Union Pacific (UP) Railroad Laramie Subdivision perpendicularly belowground, near Cheyenne, Wyoming. (footnote 1) Kinder Morgan gas controllers began contacting compressor stations at 11:40 p.m. to investigate the pressure drop. (footnote 2)

On September 21, 2025, about 1:03 a.m., westbound Union Pacific Railroad (UP) mixed-freight train MNPWC 20 was traveling on main track 3 near milepost 534.0, when the crew, consisting of one engineer and one conductor, encountered what they described to be a dust or vapor cloud near the track. At 1:04 a.m., the crew noticed a fire behind the third locomotive and the train’s engines unexpectedly shut down. The pipeline had ruptured next to the train tracks and the released gas ignited and exploded as the train passed; however, the train did not derail. About 1:05 a.m., the crew brought the train to a controlled stop and contacted the dispatcher by radio at UP’s Network Operations Center in Omaha, Nebraska. The dispatcher reported the situation to local emergency services to respond to the site. At 1:09 a.m., while stopped, the train experienced a train-initiated emergency application and the crew exited the train. Visibility conditions at the time of the incident were dark, with no precipitation; the temperature was 45°F. (See figure above.)

When emergency responders arrived at the accident location they spoke with the train crew to confirm the train’s consist. Train MNPWC 20 was a key train composed of 5 locomotives and 227 railcars (157 were loaded and 70 were empty rail cars) (footnote 3). Of the 157 loaded railcars, 57 were carrying hazardous materials (footnote 4). Due to exposure from the natural gas fire, two of the rail cars carrying ethanol on main track 3 began venting product (natural gas) through the pressure relief device.

After contacting their compressor stations, Kinder Morgan sent a gas technician at 1:34 a.m. to shut valves at the Cheyenne Compressor Station. Kinder Morgan staff manually shut down two mainline valves to isolate the ruptured pipeline segment (footnote 5). The first was closed at 2:20 a.m. and the second at 3:04 a.m.

While on scene, National Transportation Safety Board investigators reviewed Kinder Morgan’s policies and procedures; reviewed UP train crew’s employee records; visually inspected the pipeline; reviewed video footage from the head-end locomotive and drone imagery; collected physical evidence for further inspection; and conducted interviews.

The investigation is ongoing. Future investigative activity will focus on examining the physical evidence, emergency response actions of Kinder Morgan, integrity management, and pipeline failure history.

Parties to the investigation include:

• the Pipeline and Hazardous Materials Safety Administration;
• Laramie County Emergency Services;
• the Brotherhood of Locomotive Engineers and Trainmen;
• Union Pacific Railroad; and
• Kinder Morgan.

Footnotes

1. (a) All times in this report are local time. (b) The Colorado Interstate Gas 005-A pipeline is an indirect wholly owned subsidiary of Kinder Morgan Inc., owned by Kinder Morgan Energy Partners, L.P. (c) SCADA is a generic name for a computerized system that is capable of gathering and processing data and applying operational controls over long distances. (d) The Laramie Subdivision begins at MP 509 and ends at 570 and consists of multiple tracks with passing sidings. At the accident site, there were two tracks, main track 3 and a controlled siding. The subdivision is mixed with passenger and freight service at Federal Railroad Administration Class 4 speeds of 79 mph passenger and 60 mph freight, in an east/west timetable direction as noted in the North Platte Area Timetable No. 6.
2. Kinder Morgan contacted Cheyenne Compressor Station, Laramie Compressor Station, Rawlins Compressor Station, and Wamsutter Compressor Station about the drop in pressure. The pipeline was operating at 810 pounds-per-square-inch gauge before the incident.
3. A key train is defined in the Association of American Railroads United States Hazardous Materials Instructions for Rail as a train with any one of the following components: at least one tank car containing anhydrous ammonia, ammonia solutions, or material designated as a poison or toxic inhalation hazard; 20 railcar loads of any combination of hazardous material; or one or more railcar loads of spent nuclear fuel or radioactive waste.
4. Of the 57 railcars carrying hazardous materials, 35 railcars in a row on the head-end of train MNPWC 20, were carrying UN 1987 Alcohols, n.o.s. (not otherwise specified), Class 3 (flammable liquid) Packing Group II.
5. A compressor station is defined as a large mechanical facility in the natural gas industry that increases the pressure of natural gas by reducing its volume, enabling efficient transmission along pipelines.