Cars not uncoupling at crest of the hump

Most cars are MT truck mounted couplers, the others are Atlas accumate.

Long story short; the 'trip pin' of the lead car doesn't appear to be opening up when coupled to the 2nd car at the crest of the hump. Separately that trip pin does open when not coupled, but together it doesn't appear to be moving. thou it's hard to tell. One does, the other doesn't.

I've move the uncoupling magnet 'up' closer to the crest, but that hasn't changed anything.

Now if I push the string of cars with my hand the cars usually uncouple by the 'jerkiness' of my hand (for lack of a better term).

The uncoupling magnet is 1/2" from the crest. Lastly, I believe I made the crest to 'broad' making matters worse. But that is reaching for a reason this isn't working. See the attachments.

Hope all of that made sense.

 

I think there has to be absolute slack between the two cars to uncouple, so that both couplers are pulled away to opposite sides by the magnet. Any kind of tension on the couplers will likely cause trouble.

Cool that you have a hump yard. That would be fun to watch!

 

Lack of slack was my first thought, too. Most model couplers (unlike real ones) are slightly hooked. So if there's no space between, they catch each other and don't open fully. You can accelerate a whole train over an uncoupler with nothing uncoupling.

That's necessary. Real knuckle couplers (and expensive, intricate O scale couplers) have a moving tongue that traps the other coupler, or opens completely out of the way. Smaller scales have that part fixed, and the two sides spread apart to uncouple. If they weren't hooked, they'd press back their springs and uncouple while running all the time.

Makes for a Catch 22. Put the uncoupler where that car is still being pushed and it won't roll away. Put it where the car will roll away and there's no slack for the uncoupler. I guess the trick is to mount the uncoupler right where the car transitions from being pushed to rolling away. Which wouldn't be too awfully difficult--if all freight cars were the exact same length...

 

I agree with the above comments on there being a "lack of slack" that is necessary for uncoupling. The uncoupling has to be done before the first car passes the crest of the hump because after it passes the hump the slack is removed. I would try extending the magnet to include the area before the crest as well as at and over the crest. I would recommend using the small super magnets available on Ebay such as:

20pcs Strong Magnets Block Square Rare Earth Neodymium Small Magnet 10X5X2mm | eBay

These ones are only approx. 3/4 inches long and you may have to use more than one on each side of rails of the hump track. There are others available on Ebay and prices and quantities vary.

 

I thought about the magnet, but like I stated, free hand (no cars attached) the knuckle does freely open. This magnet I assume was from MT that I got back in 1996 when I built my 1st layout with a hump. There was no problem there at the time as far as uncoupling.

I also thought about extending the magnet. I'll try that.

 

Those magnets will fit between the rails w/o shorting?

 

As long as the magnets do not contact the rails. A couple of thoughts enter my old mind. One is to increase the magnets. The other is maybe level out the top of the hump a little more.

 

Make the peak less flat. Make the transition sharp enough and a lot of them will uncouple themselves.

 

A sharper decline might get too much speed on the rolling cars. Something to think about.

 

I think getting enough momentum to make it all the way to the classification track is more likely to be a problem.

 

Are you trying to uncouple in one move? If so, MT's don't work like that. I recall a Micro Trains display some time ago in my LHS. Uncoupling with magnets required a series of moves. Moving the cars over the magnet would drive the trip pins toward the edge of the rails, "opening" the coupler box. You then had to nudge the car very slightly forward to disengage the tongue, and then reverse direction to separate the cars. The coupler had to remain above the magnet, so you could reverse the train once again while the magnet drove both trip pins apart to prevent recoupling. You could then "push" the uncoupled car ahead to park it where designated.

 

That part is unnecessary in this case. That's done so the car won't be parked over the uncoupler, because then you can't couple back up to it later. But cars are never coupled back up at the top of the hump, because they aren't there any more. Gravity has moved them elsewhere.

 

I'll have to just wait until I get those magnets I ordered before I make any other changes.


When you mention speed, there also is a 'speed' problem, most of the cars are going way too fast. I tried to slow them down with a touch of grease on the axle point (1 pair only). It helps, but it's hard to get the correct amount. I had to do this 25 years ago when I made the grade excessive with my 1st hump. When I figured the grade this time I must of used poorly rolling cars as a test. My huge mistake.

 

Have any felines in residence? If so look for shedded whiskers and cut off the thinnest part at the tip then plant those so that just the tip hits just the axle. Instant car retarder. A fine bristle off a paint brush will also do.

 

No cats, but I do have brushes. No real idea just exactly how to "plant" them.

 

Its an old modeler's trick to hold cars on a sloping track and just the tip is used. Got to be fine and flexible so it will bend. Cars in a train can pass over it with no issue. Simply drill a very small hole in the exact middle of the track and plant one bristle, just one. The tip of a cats' whicker can hold a car stationary on a grade yet be flexible enough to allow moving cars to pass over with no issue. The tip should just impact the wheel axle and that is all. If more retardation is needed simply go and inch or more and plant a 2nd one. The bristle needs to be fine so think about the tip of a cats whisker it tapers to the tip of it.

 

Placement of the 'whisker' on the grade is important. You want the car to attain some momentum so some experimentation is needed. I have heard of some modelers using clear monofilament fishing line but don't know what scale they modelled. It's an alternative if the cat objects.

 

Most track products have holes in the ties now and then for track nails. Use one of those JMO.

 

But on the track it would be stationary, not with the car.
Will rabbit whiskers work? We have a lot around but no pets in apartments.