Turnout Closure rails...

[strummer]

I'm asking this here, because I'm dealing with HO track, but I guess the basic question could apply to any scale.

I have (4) turnouts in front of me:

The Kato #6  has closure rails that start at the hinged part of the point(?) and terminate at the frog, which is plastic.

The Atlas Mark IV  (a #8) is the same, except the frog is metal; the closures are the same.

A Shinohara #5 is pretty much the same as the Atlas.

I also just picked up a Shinohara #8; this has the closure rails that start at the hinged point, but then they are solid rails that run to, and help form, the frog itself.

This particular turnout seems to be the best at transmitting current throughout the piece; all the others (Kato included) show that, given the loco, there is the possibility of stalling through the frog. 

Any reason why all turnouts are not constructed this way?

Mark in Oregon

[jagged ben]

Are you powering the frog on the second and third ones?

A plastic frog will be worse for pickup, for obvious reasons.

An isolated metal frog, which is what it sounds like you've got on the second and third ones, needs to be powered with a feeder whose polarity is switched when the turnout is thrown.  If it's not powered then it might as well be plastic.

The last turnout you mention sounds like a power routed frog that gets power through the points.  You're required to put gaps behind the frog unless they lead only to stubs.  Otherwise you'll get shorts when turnouts are not aligned with each other.   Relying only on the points to provide electrical contact is actually not reliable in the long run. Additionally, since the points have the same polarity, the backside of a wheel brushing against an open point causes a short.  This was never noticed much in the old analog days, because trains usually rolled through.  But since DCC systems are a lot more sensitive to shorts, these types of turnouts are no longer considered 'DCC friendly'.   These are the reasons turnouts aren't all made that way.

[strummer]

That explains it nicely, thank you...

Mark in Oregon

EDIT: Indeed, further tests show it is "power routed", similar to the Kato product. I think I found another on eBay; made by Shinohara and sold under the "Lambert" name.