Just found this on Youtube... Not British steam, but interesting all the same. Durango & Silverton Railway, with visiting Southern Pacific 4-6-0 No. 18. Just after 35:17 the right-hand piston head disintegrates, punching a hole through the cylinder cover. Not a nice thing to happen, but there's good footage of the aftermath, the contents of the cylinder, and how the D & SR dealt with it. Interesting that the RH valvegear doesn't seem to have been immobilised. I'd have thought that the connecting rod would have been lowered off the engine, as the piston rod is unsupported in the cylinder bore when it reaches the front of its stroke. Richard.