As far as I recall, when I've seen this brake on a prototype freight car (e.g. flat, gondola, tank), there's a chain that wraps around the bottom of the brake wheel staff when the wheel is turned to set the brake manually (when the car is not in a train connected to the brake air line). That's as far as I've followed the chain by eye.
Anyone know if the chain continues all the way to the piston on the brake cylinder (passing through holes in the car framing), or if there's a combination of chain (at the brake wheel staff) and rodding (to the piston end)?
Cal-Scale (in a drawing with their HO model of the brake system) shows what appears to be a couple of chain links at the piston end which may indicate that the chain runs the entire way from the piston end to the brake wheel staff.
Staybolt,
This should help you out,a lot. Give time to load:
http://tc-nmra.org/TC-Library/Model%20Railroading's%20Dark%20Underbelly%20-%20Final%20Version.pdf
Cheers,
Frank
Frank-
Hey, thanks a lot for this link….so there is evidently a combination of chain and rod. Guess it makes sense. Chain all the way could get hung up as it passes through various frame members.
I suppose the author(s) of the Bluebook of Model Railroad Practice got their info on this subject from a Westinghouse publication. In fact, besides trying this forum, I also Googled the subject and found that Amazon.com sells what appears to be original copies of such a Westinghouse pub.
I model in the 1920s era when K brake systems predominated. I realize the brake chain component is a tiny detail, but a big part of the enjoyment of this hobby for me is making the models look as real as possible.
Thanks again,
Chuck
Generally, the chain is for a short length and helps deal with the transition from a vertical staff to the horizontal rigging below the car. The chain attaches at one end to the bottom of the staff. As the staff turns and wraps the chain around the staff, it draws a length of rodding toward the B end of the car, setting the brake.
Mike Lehman
Urbana, IL
Where the chain goes or how long it is, is really up to the design of the car. There was always chains, rods, bell cranks, and other links that would attach the brake wheel to the cylinder or cylinders. Some cars such as depressed center and well hole cars sometimes had complete brake systems on each end of the car. I had a diagram for a hopper bottom gon that had K brakes on both ends with a vertical staff only on the B end. The wrapper chain hooked directly to a separate brake beam independent of the air brake system. The air system worked on all four axles and the hand brake worked on a single truck (2 axles) at the B end. It was dated late 1800s.
Pete
I pray every day I break even, Cause I can really use the money!
I started with nothing and still have most of it left!
Pete,
Yes, lots of variance in how this all hooked up.
One thing that's clear though and may have been at the root of the OP's question. The chain is not going to run very far horizontally before hooking up to something. Long lengths of drooping brake chains are just not in the picture, because if there's much slack in a long chain strung like that, it starts drooping. And rolling down the iron, all those brakes will be released, so not something you'd want drooping there, either. It may be a rod or lever, but somehow the chain connects into something else to transfer the force properly over a sometimes considerable length of car.
Speaking of long handbrake chains, it made me think of the arrangements on later Alco Century series where the handbrake chain actually laid in a trough and some had a tube and pulley arrangement to keep the chain from sagging to low.
Don't have a photo just yet but I'll do some digging...
Take care, Ed
Ed,
Excellent example of the potential issues!
I couldn't figure out what that was when I first saw it, on a model or in a pic, never saw one in real life. Maybe some kind of strut for an exotic high-adhesion truck? Nope, just a hog trough to hold the chain up.
I love Alcos, but it's stuff like that which in retrospect may have been signs the pencil wasn't as sharp there as it used to be near the end.
Hi, Mike
Here's a couple of shots of an Alco C-424 front truck showing the hand brake chain. I'll bet the crew just loved "tie'n 'em down" They must have cranked their arms off!
That's some serious droop on that top picture!
Ed
If the brakewheel is on a vertical staff, there's a short length of chain at the bottom which is taken-up on the staff as the brakewheel is turned. It's connected to rods and levers similar to those on AB type brakes. There's usually also a length of chain at the connection to the brake cylinder - this is a manually-operated slack adjuster.Here's a modified MDC underbody with K-type brakes. The chain on the brake cylinder is the slack adjuster, and the rod connected to it goes to the short chain attached to the bottom of the brake staff (the rod on the prototype would run straight to that connection, but model clearances dictate a sharp bend to clear the trucks). The truncated rods from the brake activating levers are terminated in the centreframe, again to avoid clearance issues.
The chain connection at the car's end is only suggested, as there is no scale chain available small enough to be useable:
K-type brakes could also be manually operated by power hand brakes. In that case, the chain would be immediately below the handbrake housing, and would connect to a rod which extended downward to a fulcrum. This changed the motion from a vertical one to a horizontal one, and was connected to the brake cylinder in the usual manner.
Here's a car with split-K brakes (added to a Train Miniature car formerly with AB brakes cast as part of the car's floor/underbody). The rod for the handbrake is the lower one on the left:
And a view of the car's "B" end, showing the power handbrake:
Wayne
Chuck,
Glad to have been able,to help you out, those diagram's in that link,are really helpful and your right,they did come from the horse's mouth,so to speak! Have Fun!
Edit: BTW, To The Forums.