I have a question that hopefully someone here can answer

[Starguard]

A discussion rose between me and a few rail fan buddies of mines about train couplers..

How is it that train couplers can pull so much weight without being ripped from the cars they are attached to? The rear coupler on an locomotive thats pulling over 100 loaded cars has to be able to withstand the torque of pulling well over 500 tons (if not more).

Anyone understand the physics behind this?

 

[cascaderailroad]

A train gets going at a slow speed, with gradually increased tugging.

The inertia of a rolling train has very little stress on the couplers, as they are runaway wagons just coasting along.

On an uphill or downhill gradient, the engineer knows that excessive throttle, or excessive braking can cause breakage, and knows quite alot about proper train handling.

Some trains are 14,000 tons, and DPU trains are much more.

The swiveling knuckle is designed to withstand a train weight, and is designed to break, before the draft gear breaks.

The Knuckle Pin usually breaks before anything else does.

The Lock is a block of steel that drops into place between the coupler body and the knuckle.

Violent slamming of couplers together, and yanking couplers can result in breakage:

 

[rweber95]

A discussion rose between me and a few rail fan buddies of mines about train couplers..

How is it that train couplers can pull so much weight without being ripped from the cars they are attached to? The rear coupler on an locomotive thats pulling over 100 loaded cars has to be able to withstand the torque of pulling well over 500 tons (if not more).

Anyone understand the physics behind this?

Have a read of the article in this link http://www.alkrug.vcn.com/rrfacts/hp_te.htm. Al Krug is a real RR engineer that does a good job of explaning TE, HP and the effects of train weight and track grade. There are some numbers but no math that you have to do, he does it all and explains it very well.

Bob Weber

 

[whitepass]

Most of the wight is on the rails not the couplers.

 

[Dap]

. . .has to be able to withstand the torque of pulling well over 500 tons . . .

And technically, it is not torque(which is a rotating force), but rather tension or stretching.

 

[Starguard]

Thanks Guys :Y: