Have you ever seen anyone bypass the warning arms and lights at a Railroad Crossing?

I have, but no crash.

I see other drivers do that all of the time.  That's something I would never do because I have nightmares about train crossings.

I have seen others and I have done so. A train was completely stalled about 100 yards from the crossing.

Sure, but only when the train could not be seen or heard. 

No I haven't, but accidents and near-misses led the authorities in Britain eventually to replace most single-lane barriers as in that video, with double ones; and many of those also have folding slats that block the gap below the arms. Where possible roads cross main lines on bridges, and there are no level-crossings at all on the motorways.

The remotely-controlled barriers had originally replaced massive double gates that when open to traffic barred access to the railway, but these were manually-operated from an adjacent signal-box or by a dedicated crossing-keeper, many of whom lived in adjacent cottages built for the purpose. (The railways in the UK are all closed to unauthorised access and farm animals by full-length fences with appropriate gates.)

I watched that video a few times to try to understand another aspect of the situation. I think the motorist was intending to turn right, so had only one lane on the main road to contend with, but I can't see any room for his car to wait between the far barrier and the main road until the traffic clears. So if he had escaped the train he would probably have caused a serious road accident instead.

Also the road is clearly wet, so reducing the stopping distance and adding a skid risk by driving across the rails at an oblique angle.

Did he survive?

I have seen a video elsewhere, of a huge articulated lorry apparently stalling on a level-crossing, somewhere in the USA but I don't know where. The driver jumped down and ran clear - a second or so later a locomotive hauling a long train of shipping-containers hit the vehicle and dragged it some way along the line. Like in that above, though with far greater masses and a slower train; but at least no-one was hurt or killed.

''''

I have had one very frightening brush, several years ago now, with these things.

I visited somebody living in a rural home, to help him with something. In return he treated me to lunch in his local pub, about quarter of a mile away but on the opposite side of a level-crossing on a twin-track main line carrying trains probably running at about 90mph. 

He was in a wheelchair but able to propel it himself, and as we approached the crossing he described being caught one day as the barriers started to descend. At the same time his chair wheel caught in a patch of gravel. The barriers were rather late and it was by sheer survival instinct that he grabbed a fence-post and wrenched himself clear as the train caught the chair and threw it some fifty yards down the track.

Luckily a motorist stopped by the crossing was a nurse and able to help him properly!

I shivered, and kept a very close watch as we crossed but we did so uneventfully, with him pointing out where the gravel patch had since been asphalted over.

One the way back I helped him up the rise to the crossing, by pushing. Just as we passed the posts the bells rang, lights flashed.... I grabbed the chair and pulled hard, back down the ramp just as the barriers came down. Seconds later the train flashed by in a blur.

Frightening.

Dumbest ways to die ...