RideMan Asks: That track segment in the Valravn Preview Center...

I think by the brake assemblies, Rideman is hinting that because of how the brakes are setup, it would make sense for the first part of the brakes be wider so that there's less wear and tear when receiving the train. Looking at it from the side it looks like this...

<--------- Direction of travel

-()---------------------()-------------

The parenthesis represent the calipers and the lines represent the actual brakes. If you notice on the right side there is a longer length of brake with no caliper behind it. Whereas on the left side there isn't.

If you look on older rides top view of the brakes, when closed look like this

>-------------------<

Am I on the right track?

~Rob

That's a pretty clever observation. I hadn't even thought to look at the shape of the calipers compared to the pads.

RideMan said:

I also think it is interesting that nobody picked up on the clue that initially got my attention. I'm going to let this sit a little longer and see if anybody notices.

For lack of a better term, the steel "posts" are on the back side of the brakes to absorb excess forces put on to the calipers in the direction of travel. Am I close, Dave? See here on Griffon:

I had not noticed those. Very nice.

[image][image][image]Excellent, Kirk. In fact, here's a close-up (assuming I can get PointBuzz and Flickr to play nice...)--

Valravn brake assembly[/image]

The brake caliper has this pair of I-beams at the downtrack end, and the brake pads actually ride against the I-beam. When the brake closes on the spine of the train, the train's momentum is going to want to pull the brake pads in the direction of travel. These I-beams are in place to hold the brake pads in place and ultimately to hold back the train. Since the I-beam is at the left-hand side of the brake caliper, clearly the direction of travel here is right to left. Also, the brake pads are tapered to form a wider opening on the right hand side, so that the train can enter the brake even when the brake is closed.

If you look a little closer, you can see that there is a Zerk fitting right in the middle of the edge of the I-beam where the end of the brake assembly rubs against it, and in fact it looks like there might even be a wear plate on the end of the brake assembly. That's to allow for lubrication of that side of the I-beam to keep the brake moving freely in and out against the I-beam.

There are a couple of other interesting details about this brake assembly.

Valravn brake cylinder[/image]

Notice that the brake cylinder is not attached to anything but the brake assembly; it is not rigidly attached to the caliper frame or to the track. This is a rather clever idea because it means that with no adjustment needed, no extra hardware, and no real effort, it will *always* apply equal force to both sides of the brake caliper. Because all it does is to push the two caliper ends apart or pull them towards each other. Note also the long bolts used to hold the cylinder together. That's because there is a very heavy spring in the bottom (to the right in this photo) of the cylinder. Note also the tiny little prox switch on the cylinder rod to detect the movement of the piston.

Finally...

Valravn brake assembly[/image]

You can also see how the brake is "wired up". Compressed air comes in through the galvanized pipe and then through the two hoses to the cylinder caps. Applying pressure to the top of the cylinder will retract the rod against the spring tension, which will pull the bottom of the caliper together, which will in turn pull the brake pads apart at the top. When the air pressure is released, the springs in the cylinders will push the rods back out, squeezing the pads together at the top and thus slowing the train. The spring tension must be enough to force the pads together far enough to hold tightly against the sides of the train. When the train enters the brake caliper through the tapered end, it will force the brake open against the spring tension, but the spring will offer enough resistance to stop the train.

--Dave Althoff, Jr.

And of course, not only did my image links not work, I also can't get the post editor to load. So here are the URLs for the images that were supposed to be included in my last message...

The end of the brake assembly, showing the I-beams: https://flic.kr/p/zfHkxd

Side view of one of the cylinders: https://flic.kr/p/zgYjmq

Brake actuator, showing the associated plumbing: https://flic.kr/p/ym9bFR

--Dave Althoff, Jr.

What a terrific explanation Dave. I appreciate the simplicity in B&M engineering.

I noticed in your 3rd photo that the whole assembly is attached to the track spine with only eight fairly small bolts. It seems like this would be susceptible to sheering, however the downtrack end with the I-beams is possibly butted against the steel the rails are attached to? It seems like a lot of horizontal force for just the bolts.

Your images were to HTML pages, Dave. Flickr doesn't appear to let you embed images from other sites, it seems. Also, text version is (remove spaces) [ image = url ]

Very nice explanation Dave. I did notice the cleverness of the brake cylinder setup, the other details totally escaped me however. Looking at all the details now, it is pretty obvious as Jeff pointed out, that the piece goes before the transfer track.

I will agree with Jeff about the holes for alignment pins. The opposite end of track does get bolted to another piece, as you can see in other photos that there are two bolts aligned vertically holding protective caps on rails.

But, looking how small this piece is, it is possible that it will take two pieces to equal the length of transfer piece. So, the piece that it is bolted to could have the kicker tires, making this part of the transfer track. So, it's either first piece of transfer or the final piece before transfer. I am leaning toward the latter.

Good discussion.

My guess is that this is the last piece before the transfer, as the transfer would not only have finish paint on both ends, but also a drive assembly as well as, or more likely instead of, a brake. Also, I would expect the transfer to be flat, not to have a vertical kink at one end.

There is one thing missing. On GateKeeper, the rail is split at the end where it mates with the transfer, in the style of Vekoma's bolt together track. The rail on this Valravn piece just has a recessed plug.

--Dave Althoff, Jr.

That's my thought too. The size and shaping of the piece don't really fit anywhere else. The details (brake orientation, lack of drive wheels, etc) just reinforce that position.