Two things you should keep in mind: period of resonance, and reflected shock. The latter was a critical (although at the time, unrecognized technically) reason why John Stevens' "temporary" track structure became the mainline standard instead of granite blocks supporting fishbelly rail, or longitudinal baulks spanning point 'foundations', or cast slab track...
REALLY bad track is where joints are so unsupported that the rail physically bows UP above track level when wheels are loading both ends. If I had not seen photographic proof, I wouldn't have believed it possible.
OvermodTwo things you should keep in mind: period of resonance, and reflected shock. The latter was a critical (although at the time, unrecognized technically) reason why John Stevens' "temporary" track structure became the mainline standard instead of granite blocks supporting fishbelly rail, or longitudinal baulks spanning point 'foundations', or cast slab track... REALLY bad track is where joints are so unsupported that the rail physically bows UP above track level when wheels are loading both ends. If I had not seen photographic proof, I wouldn't have believed it possible.
Recall riding the 'front porch' of a locomotive heading down a long industrial lead that could have been maintained at a higher level. Jointed Rail. Every time the lead wheels of the locomotive occupied one end of a rail, the far end of the rail could be seen 'jumping up' a inch or so, as the engine continued on, the rail would settle back down and the situation would be repeated as the next rail had the weight of the engine applied to it.
Never too old to have a happy childhood!
OvermodREALLY bad track is where joints are so unsupported that the rail physically bows UP above track level when wheels are loading both ends. If I had not seen photographic proof, I wouldn't have believed it possible.
There used to be a video around of stick rail wherein the stick itself was completely unsecured to the ties. Only the joint bars kept it in gauge. And, yes, the ends did flop around a lot as cars passed over it.
Larry Resident Microferroequinologist (at least at my house) Everyone goes home; Safety begins with you My Opinion. Standard Disclaimers Apply. No Expiration Date Come ride the rails with me! There's one thing about humility - the moment you think you've got it, you've lost it...
David1005 Equipment engineers look at the track as the primary suspension with a spring constant of about 1,000,000 lbs/in.
Equipment engineers look at the track as the primary suspension with a spring constant of about 1,000,000 lbs/in.
I'm curious about the length of track assumed for that figure. Since this ties in with truck suspension, this might be the modulus for one wheelbase length.
You are correct that an infinite modulus would worsen loading from flat spots on wheels.
BaltACD Every time the lead wheels of the locomotive occupied one end of a rail, the far end of the rail could be seen 'jumping up' a inch or so, as the engine continued on, the rail would settle back down and the situation would be repeated as the next rail had the weight of the engine applied to it.
Every time the lead wheels of the locomotive occupied one end of a rail, the far end of the rail could be seen 'jumping up' a inch or so, as the engine continued on, the rail would settle back down and the situation would be repeated as the next rail had the weight of the engine applied to it.
(and then there is the common issue of locomotives crawling-up to a turnout to the square joints three feet in front of the switch points. Bubbawits switchman can't throw the switch because the switch points and stockrail are jammed-locked together ... cue up the whiny switchman "switch hard to throw music"...)
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