QUOTE (Brian Considine @ 13 Dec 2008, 12:34) <{POST_SNAPBACK}>& (AFAIK) suffered serious damage !
Mallard was not the only steam loco to suffer serious damage following a high speed record run, the damage usually happening after steam was shut off at the end of the attempt. The most common explanation I've seen is that when the regulator was closed the exhaust steam's cushioning effect at the end of the piston stroke was removed and the unrestrained momentum of the reciprocating masses led to the bearings overloading. I understand it became the practice not to close the regulator completely to prevent this occurring.
Jerry
Mallard was not the only steam loco to suffer serious damage following a high speed record run, the damage usually happening after steam was shut off at the end of the attempt. The most common explanation I've seen is that when the regulator was closed the exhaust steam's cushioning effect at the end of the piston stroke was removed and the unrestrained momentum of the reciprocating masses led to the bearings overloading. I understand it became the practice not to close the regulator completely to prevent this occurring.
Jerry
