I see your point, but accidents don't just happen. There's nearly always an identifiable cause which, at some point prior to the incident, could have been avoided. Sometimes a component wasn't designed properly, equipment wasn't correctly maintained, safety protocols were inadequate, or (often) somebody did something wrong. Perhaps a procedure wasn't followed completely or safety rules were violated. Point is, most accidents are not truly accidents - they wouldn't have happened had everything been done properly.
Just because it happened after hours and didn't involve the public doesn't make it any less important. You should always be thankful that an accident didn't involve passengers and nobody was seriously hurt, but mindful that whatever circumstance(s) allowed this "accident" to happen could strike again, only next time it might be a fully loaded train.
Of course, our discussions here accomplish almost nothing towards such goals, but again, its a Disney related topic on a Disney message board. It's what we talk about.