​ This is preliminary information, subject to change, and may contain errors. Any errors in this report will be corrected when the final report has been completed.

On September 8, 2022, about 2:40 a.m. local time, a conductor and engineer of Union Pacific Railroad (UP) train ISILB5-07 were killed when the train collided with railcars stored in a siding near Imperial County, California. [1]​ The train was traveling eastbound about 28 mph on Mainline 2 when a UP dispatcher routed it into the west end of the signal-controlled siding (Bertram siding) at milepost 646.1 on the Yuma subdivision. The train then collided with 92 empty intermodal railcars that had been stored at milepost 646.3 since December 2021. The two lead locomotives and one intermodal railcar of UP train ISILB5-07 derailed, along with two of the empty stored intermodal railcars. (See figure.) At the time of the accident, conditions were dark, and the weather was clear, 86°F, with no precipitation. Damage to track and equipment was estimated by UP to be about $1.2 million. UP train ISILB5-07 consisted of two lead locomotives, 122 loaded intermodal railcars, and two locomotives on the rear end. 

​ While on scene, National Transportation Safety Board (NTSB) investigators documented locomotive and track damage, collected forward-facing image and event recorder data, reviewed signal and dispatcher logs, obtained radio and telephone recordings, gathered photographs and drone footage, and conducted interviews. NTSB’s investigation is ongoing. Future investigative activity will focus on UP dispatcher operating procedures, rules and procedures regarding the long-term storage of railcars, and UP’s signal and train control system.

Parties to this investigation include UP; the Federal Railroad Administration; the International Association of Sheet Metal, Air, Rail and Transportation Workers; the Brotherhood of Locomotive Engineers and Trainmen; the Brotherhood of Railway Signalmen; and the California Public Utilities Commission.​​