I know its off topic. Does anyone have or know a link to what all the drive rods and bars on a complex steam engine do. Or a video of what all the tubes and stuff do.
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You need the Model Railroad Cyclopedia. Or an older 1990s copy of OGR, where we did some of that using a drawing from Hundman with permission.
Very nice links. Brings up a question I have not found the answer to - take an older 4-4-0, with a very long snout. How is that engine, or lead, truck pivoted? Or is it? Or did they keep the front end so light that the truck could move from side to side just like our models? This is probably the wrong place to ask, but that detailed 4-4-0 triggered it.
Here is part of a post from: http://cs.trains.com/mrr/f/13/p/190994/2085730.aspx
"Next up is a Gresley two wheel lead truck:
Again, you can see a round plate on top that supports the locomotive's frame. The top hinges for the swing links can be seen on either side of it. The long tongue to the right of the locomotive actually goes back and attaches to the loco frame with a pivot. When the truck rotates, it rotates around the pivot at the end of the tongue (out of the picture to the right), while the round plate on top supports the locomotive frame, the rest of the truck moving laterally by means of the swing links. This is an adaptation of the original Bissell design.
Last and most certainly least, this is a four wheel pilot truck I built for a live steam 4-4-0:
It is a little crude, but the basic elements are there. The locomotive frame bolts to the rectangular plate at the top center of the truck. That plate is attached to the kingpin, which rides in a tapered roller bearing to allow the truck to swivel. The housing for the bearing is then supported by four swing links as seen in the picture. Those links go to a sub-frame for the truck, which is then supported by the springs to the main frame of the truck. Note that when the kingpin is centered on the truck, it is at its lowest position. As it moves to either side, it will actually rise so it transfers more weight to the pilot truck. This is what guides the locomotive around the curves. Again, this is somewhat different from a prototype 4-4-0 pilot truck, but just mainly due to the fact that I used coil springs instead of leaf springs, which made it necessary to change the frame. More sophisticated four wheel lead trucks used the heart shaped rockers, which gave a more positive centering mechanism and an accelerated rate of weight transfer to help guide the engine around the curves."
Larry
