I have no pictures but there is a long vertical rod that reaches from under the frame to above the roof. On the top is the brake wheel. On the bottom, there is a chain bolted to the side of the rod. As the rod is turned, the chain wraps around the rod to tighten the brakes. the chain pulls on the lever that is actuated by the brake cylinder. This applies the brakes. There would usually be a metal loop fastened to the frame that would cradle the chain so that it didn't droop down too far when the brake wheel is released.
I model the pre-airbrake era, so there's no automatic brake equipment on this, just the manual stuff. The long lever on the right connects to the brake wheels on either end of the car. (If you're modeling a freight car, then there would be no need for the other half of the arm, just the pivot and the arm going to the end with the brake wheel.) The arms in the middle go to the brake levers on the cars.
The history of freight car brakes is a long one well chronicled in White's book on American Freight Cars.
Essentially uo to the 1880's brakes were mainly manually applied by brakemen actuating levers as shown on Kevin's model. In 1883, trials were held to find a better braking system ... westinghouse proved the efficacy of air brakes over vacuum brakes ... and subsequently safety laws were introduced to bring all cars in interchange service to an airbrake standard. Several variations in air brakes were used over the years the two most popular being the K and then AB systems.
Beneath the cars, train lines and air actuated levers were introduced and above, brake wheels on staffs for manual operation continued from the roofwalk till the early 20s. These were then replaced by wheels on the carends of housecars This remained the standard for the next 50 years when safety changes led to the wheels being placed low on the car ends and roofwalks were removed from all housecars.
The differences between K and AB as well as other systems are explained in White's book.
I found a 'print'/ picture of an archbar truck that showed the actuating lever sticking upward, midway-above the axle. The linkage would attach to this and apparently pull the lever(s), toward the middle of the car thus setting the brake. In the pic, it appears the brake shoes are pulled outward to the 'off' position by springs attached to the bolster. Of course there would be another lever arrangement connecting the second axle in the truck. I'm building some 'skeleton' log cars and wanted to duplicate whatever braking they had-turn of the Century and before. In pictures one can see the wheel and locking pawl system that wound /pulled the chain-in this case mounted on the center 'beam'. I can not, however, see brake shoes as described above. Therefore, I'm still not sure how the bracks actually worked, or if they were somehow hidden inside.
I don't have a pic. But they're out there on the web, try Googling 'disconnects'. The earlier ones had a beam on the 'outside' of each truck, to which the brake shoes were mounted in the 3 & 9 o'clock position. By some magical (and very simple--which is why I didn't keep the pic-- [slaps self upside the head]) the crew walked alongside and turned the brake wheel, which pulled the two beams together, in the direction of the kingpost.
Obviously, if they let the train get going faster than a slow trot, things could get grim.
Yep, it's always that simple....yet magical, stuff that evades us! I've seen some of the pics with the 'bar' carrying the shoes. They never seem to think about the guys who scale build. You know, here's a pic of the wheel and here's one of the brake shoe......
Brake systems worked off of simple leverage. As soon as one shoe made contact with the wheel, it became something of a fulcrum which then allowed the other shoe to press against the other wheel. In the photo above, the linkage in the middle that ran to both trucks also served a similar function. As soon as both shoes on one truck were applied, the lever stopped moving, and became a fulcrum which began to pull the lever on the other truck (First against one axle, then the other). Once all brake shoes are firmly against the wheels, that's the point at which the brakewheel goes from simply moving the shoes against the wheels to applying serious pressure to stop.
Here's a drawing of typical brake rigging on a truck.
I think the one I have in mind(?) was a tad simpler than that one. Seems like it had just one pivot bar. I kick myself for not copying it but I remember thinking, "Huh. That's simple enough."
At any rate, the dwg doesn't show where the brake wheel/chain would hook up, though there's only one obvious place: the bar with the holes in it. Right?
Cap: get yourself a truck and fasten it down. Build up the brakes 'n beams and hang 'em. Now, locate the bwheel and chain wheresoever it suiteth thee. With K's dwg and a length of trial chain, I bet you'll come up a happy camper.
I'll go looking this afternoon. Got to go spend some more of my FIRST EVER retirement check.
Posted By Cap'nBill on 02/03/2009 2:38 PM
SteveC: not sure why your post didn't show up here, came to my email. Good references, I especially like the Trainz layout..great aid in designing a layout. Good pics of the AMS disconnects! Bill
Don't know, it was there to begin with, I did go back to edit something. Maybe I clicked something at the wrong time and wiped it out???? Sorry about that.
I'm having trouble doping out where the brakewheel chain should attach to K's dwg. Should be simple, but I'm sorta tired at the moment. Could that be an air-operated setup? No, it'd still have to have a brakewheel... I'm goin' ta bed!