05-18-2016, 10:18 AM
(05-18-2016, 09:43 AM)Markster Wrote: I'm very active in these things
I know you are, which is what baffled me about how you would get stuck in the closure
Moving on, I discovered the answer to something that had been bothering me about the design of the catenary for some time. The catenary is divided up into sections, about a kilometre or two long. At each end (not one end - this is important), there is a counterweight tensioner which uses a pulley arrangement to dramatically increase the tension on the line (small weight = big force).
That's all fine and dandy and works great, except that with two floating ends, nothing is defining where the whole catenary string wants to be in the direction of travel of the train - ie, parallel to the rails. You could grab any point on the whole stack and pull it one way or another, and all of the outrigger arms that support the catenary are on hinges so they'll pivot to wherever.
What I found last night, pleasantly: Exactly halfway between the counterweights, there's a "<>" arrangement of steel ropes that define the angular location (position) of those outrigging arms - providing an anchor point. So from this centre anchor, the tensioner at one end is responsible for tensioning that half of the catenary stack, and the tensioner at the other end is responsible for that end.
Something I should have figured out long ago, but it was just one of those "...oh!" moments while looking at it last night that made me smile.