They're closer to 200 tons these years, but you may be correct. I don't know the materials involved, and if a fireman or two can carry them, they're probably not heavy enough to launch a locomotive over them. So, agreed. But my point was, if they present a barrier to the rolling stock, and with their apparent angled faces, those items can ride over them without derailing in all probability. Just a really nasty, and noisy, lurch and bangs. Further, any train running at more than 20 mph, and with no prior warning from dispatchers, is going to hit that....so, I would think they offer no 'warning'.Over? No way. 100 ton loco will slice through easily.