Absolutely, I've known several conductors who have derailed trains more than once and I'm in the group as well. It's incredibly common, actually. Most derailments happen at low speeds, within the railyards commonly 10mph or less. You don't hear about them because they're just not that exciting I suppose.

Yard tracks are typically more neglected than the mainline tracks. Lower speeds in yards mean even if a derailment occurs it won't typically be all that catastrophic, so the terminal managers play a game of odds. They'd rather take home a fat bonus at the end of the year for having few or no accidents in their yards.

The terminal itself has a set fund for track maintenance, and if they can avoid spending it all, there's a nice percentage added to the terminal managers yearly bonus. So even when a derailment occurs, often times the manager will not report it. They call their maintenance of way(track laborers) out and sweep these things under the rug without anyone knowing the score.

I'm not just speculating, I've been the conductor responsible for two derailments that I've watched managers cover up. Usually the wheel flanges tear up the wooden ties a bit, and the weight/friction/force of these things will also often chip, bend or break switch points.

There's a number of ways trains can derail. They have manual derails that are big bulky iron ramps essentially that railroad workers will purposely set up to cause derailments. That sounds crazy, but they're really for protection.

You line them on the outer ends of the yards, so trains don't derail out onto the mainline during switching operations within the yard. They protect the fast moving trains from the dangers often occurring in yards. More often than not, a derailment isn't a human factor incident though, it's due to poor rail maintenance.

I eventually promoted to locomotive engineer(the person that operates the locomotives/trains) and while at the controls I've derailed a couple times as well. You're just doing your job, running the train at the prescribed speed limit and the next thing you know you're on the ground(the wheels are).

There's actually pilots on the railroad too. Pilots and firemen, neither are probably what you'd expect. A fireman is a student engineer. In the old days with steam locomotives, the student engineer seldom got to run the train himself. His job was primarily to load the wood into the fire(fireman).

A pilot is when you have an engineer called on duty to run a train over a territory of rail that he hasn't been qualified to run on yet. Every engineer knows what territories he's qualified for and which he's not. So when the crew caller tells him he's going to such and such location, he informs the caller that he'll need a pilot. A pilot is a qualified engineer on said territory, he'll pilot the other engineer through unfamiliar sections of rail. Eventually the engineer becomes comfortable with the new territory after having enough pilots and a manager of road operations will ride along and qualify him on that territory.

Derailments are seldom career ending mistakes, they're usually kicked under the rug as I mentioned. The derailments that will get you fired are the ones you're undeniably at fault for. So like running through a switch the wrong way, or over a manual derail, or beyond a red signal into another train, etc.

Hope that all helps to answer your question.