Need to look at getting rid of shelf couplers on upgraded tank cars. Shelf couplers means that you never just derail one car, but instead you derail several because the knuckle can't slide out of the coupler cause the cars to come apart so the air lines don't come apart until you have a huge mess. Then, because shelf couplers are so strong, the drawbars break instead leaving a harpoon long enough to poke through the new mandated bulkheads on the tank cars. I've been looking at photos of recent derailments, you should look too, many ruptured cars were hit by shelf coupler drawbars, and many simple derailments grew much larger because of shelf couplers won't come apart and drag more cars off the track.