My guess is the turnout wasn't designed for extended use with those heavy locos with three wheeled trucks (bogeys). At some point the guide rail must have move beyond its limits to prevent a wheel flange from climbing up onto the rail. I also assume the frog must have either cracked or was getting pushed down beyond its design limits under the weight. As the train accelerated over the frog the side force vectors on each passing car decreased while the forward force vectors increased (due to the acceleration). Finally the forward forces overcame the side forces resulting in a wheel flange rolling up on the rail. The rest is history.
My guess is the turnout wasn't designed for extended use with those heavy locos with three wheeled trucks (bogeys). At some point the guide rail must have move beyond its limits to prevent a wheel flange from climbing up onto the rail. I also assume the frog must have either cracked or was getting pushed down beyond its design limits under the weight. As the train accelerated over the frog the side force vectors on each passing car decreased while the forward force vectors increased (due to the acceleration). Finally the forward forces overcame the
ReplyDeleteside forces resulting in a wheel flange rolling up on the rail. The rest is history.
Comment by Bisbee Jim