John P
Active Member
Sorry to revive an old topic, but I'm a new forum member and currently working on a small hump yard.
My background includes physics...
more prototypical would be to use a pressure sensor placed under the track section at the top of the hill to weigh each car at the top to predict the speed at the bottom -- but there's more room for error there due to differences in the rolling friction of each car
Physics, eh? That sounds like a repeat of Galileo's demonstration that heavy objects fall faster than light ones. Or am I remembering it right?
As always in these discussions, it's all about "retarders". Folks, why are retarders needed or used? To slow the cars down, you say. Then I'll ask why the cars were going so fast to begin with. And there never seems to be an answer to that.
Once I calculated how high a hump should be on a model railroad in order to get cars rolling at a scale speed. The result was so absurd that I ended up repeating the math three times. It's a good demonstration of how gravity and energy don't scale well.
I think any model hump yard that involves cars running much above scale speed has already failed. If I can't figure out a way to keep the speed realistic, I will never build one (and so far it hasn't happened).