What type of coupler? Is my incline too steep?

[nemia]

A couple questions, related to the Yard Boss set I bought for my son a couple months ago:

1. What kind of couplers does this have? I've done some googling, but to my surprise, I still can't figure it out. 

2. I purchase the Bachmann 16-pier set and some extra track to add to the 24" circle to make an under/over figure 8.  However, with more than one car attached to the engine, the engine slips on th incline.  Even spreading the piers out so they are a couple track legths from each other (so that there are only 2 or 3 track segments with no pier, it still slips.  Even adding a 4 straights and not using the tallest pier, it still slips a litle with 3 cars attached.  Am I expecting too much (the box made it seem as if it was meant for basic figure 8s)? 

Thanks!!

[ABC]

Did your loco come with traction tires? If so, are they still there (They will appear as black bands over a wheel on each side)? Also, your track could be dirty, your loco's wheels could be dirty, your loco could be over lubed. Don't expect a $25 engine to run like a $75 engine. The loco in your set probably does not have the best pulling power. I believe it comes with a 0-6-0 with USRA tender from Bchmann's standard line. Try a spectrum loco and see if you have better success.
Also, if your set is newer they come with dummy knuckle couplers, if it is older stock which is a good possibility, then it has NMRA couplers. If you use MT or other working knuckle couplers you might have better luck.

[skipgear]

I believe the riser sets give you around a 4-5% grade. Much too steep for most applications. The rule of thumb when designing a layout is to keep the grades less than 2%.

For guestimation purposes, every 1% increase in grade cuts your train length in half. The 0-6-0's will pull an 8-10 car train on level so the numbers you are seeing are about right.

As far as couplers you have 3 options:

Rapido - A rectangular hook
Dummy Knuckle - looks sort of like a real coupler. Will couple with Micro Trains, Atlas Accumate, and McHenry knuckle couplers.
Operating Knuckle - only on the most recent releases, will automatically couple with the other couplers and can be used with magnets under the track for automatic uncoupling.