Calgary Transit trains have a deadman override mechanism consisting of a floor pedal and a button on the cab’s dash. One or the other must be engaged by the operator at all times for the train to run. In an emergency, the deadman is engaged and the train stops. After an operator’s shift, a first aid kit was found jammed between the override button and the dash, allowing the train to run but preventing the deadman from engaging in an emergency. When confronted, the operator denied jamming the button, later admitted the misconduct and then denied it again. So the city fired him. An arbitrator upheld his termination, although he had no prior disciplinary record. The circumstantial evidence was compelling against the operator, who wasn’t credible. In addition, the seriousness of his misconduct and the potential tragic consequences of that action were obvious, noted the arbitrator [Calgary (City) v. Amalgamated Transit Union, Local 583 (Khan Grievance),  A.G.A.A. No. 4, March 11, 2016].