Yes, we could have continued operating without a horn. The issue that kept us from moving that train was the fact that the tree came to rest on the train, with a significant portion of the trunk leaning against the train in the vicinity of the passenger windows. The assessment was that if we tried to move the train at that time without assistance from CN, the tree would intrude into the passenger compartment, break the windows, and open the car to the environment.
On January 26th, 2023. See this statement in context.