Kato catenary question

[velotrain]

I had been given to understand that (Japanese) catenary pole arms alternate between short and long, to create a zig-zag in the wire, so a groove isn't worn into the pantograph.  I bought a package of the Kato 23-058, the Single Track Warren Brace Catenary Pole, and an illustration on the back has me confused.

 

 

 

 

Why are long arms used on the inside for half of the turn, and short arms used on the outside for the other half?

 

Why does the straight at the top alternate between long and short arms on the outside of the track, while the straight at the bottom uses long arms on alternate sides of the track?

 

I notice that the actual hanger is facing in opposite directions on the two arm types, and it appears that there may actually be little difference in the distance of the wire from the pole?  (based solely on the illustration)

 

 

[katoftw]

Correct on your hanger/arm observations. Just like in real life.

[velotrain]

 Most helpful.

[Kiha66]

Why are long arms used on the inside for half of the turn, and short arms used on the outside for the other half?

 

Why does the straight at the top alternate between long and short arms on the outside of the track, while the straight at the bottom uses long arms on alternate sides of the track?

 

I notice that the actual hanger is facing in opposite directions on the two arm types, and it appears that there may actually be little difference in the distance of the wire from the pole?  (based solely on the illustration)

Why are long arms used on the inside for half of the turn, and short arms used on the outside for the other half?

I think this is just to show that you could use either mast for curves, the hanging arm just needs to be always pulling the cable towards the wider end of the curve to keep the tension in the wire.  I've seen masts on both the inside and outed of curves in US practice, so i think the arrangement on diagram is just to use all of the masts that come in the kit.

 

Why does the straight at the top alternate between long and short arms on the outside of the track, while the straight at the bottom uses long arms on alternate sides of the track?

Again, I think this is just showing the options for mast arrangement, as both will alternate which side the cable is pulled with each mast, keeping the cable zig-zaging across the middle of the track.  Personally I cant remember seeing the bottom type in practice, but that was probably due to it being easier to install all the masts on the same side of the track rather than anything wrong with this method. 

 

I notice that the actual hanger is facing in opposite directions on the two arm types, and it appears that there may actually be little difference in the distance of the wire from the pole?  (based solely on the illustration)

From my understanding this is by design, the cable will be a little closer to the pole in type 2, and a little farther in type one.  Like you said, this is to have the cable zig-zag to create even wear pantograph, although from my understanding this is only a problem on lines with exceptionally smooth track work, american prototype mostly relied on natural sway (induced by the uneven breaks between rails) to cause even wear.

 

Hope this helps,  

-Sam

[katoftw]

http://www.railway-technical.com/ohl001.gif

 

link:- http://www.railway-technical.com/etracp.shtml

 

the arms actually pull the wire away from the center line of the rails. hence you'll see the alternating pattern like in the kato diagram to get the zig-zag effect.

 

on corners, the wire is always pulled to the outside of the curve. so depending on which side of the rails the overhead mast is, dictates which type of hanger and arm direction is used.

 

kato's diagram just shows four possible fitments. up to you to choose what works best for you, whether prototypical or not.

Edited December 19, 2016 by cteno4
Photo link

[velotrain]

Thanks, guys. 

 

The diagram on the package didn't seem to agree with what I had heard, so it didn't make sense.  I would have expected Kato to indicate best practice, not all possible combinations.

[katoftw]

Best practice is a rather vague statement.  Best practice changes between companies, geographical requirements, railside requirements, era of use etc.  So as I said, just use the combo that is, a- best for you, or b- prototypical for your needs.