Self - Guarding Frogs

[trisonic]

This photo of two of the new "heritage" liveried NS locomotives (EMD SD70ACe) show up (what looks to be) a recently laid turnout with self-guarding frogs.

 

1. Has anyone built such turnouts in a to scale layout? Do they work well scaled down?

 

2. Do any exist within the British Isles?

 

They obvious work with full sized locos (there aren't many heavier than an SD70ACe). The frog has taken a big ding sometime in it's life. Would they work well at normal operating speeds?

 

 

http://www.railpictures.net/viewphoto.php?id=398471&nseq=0

 

Anyway I thought I would share.

 

Best, Pete.

[Re6/6]

Yes Pete, I've seen pictures of some of the latest S & C work with these 'checking' fittings on slips in the UK. Whether they're the 'norm' now for new work I don't know.

 

I'm presently building the new scissors crossing for Matford...(the third one...the others went in the bin!) and it will have these style of fittings at the crossing points.

[martin_wynne]

Hi Pete,

 

Self-guarding frogs (i.e. no check rails needed) depend on the width of the wheel to work. The raised portion bears against the outside face of the wheel, so all vehicles must have the same wheel width. In the UK wheels vary in width (wagon wheels are narrower than loco wheels), so self-guarding frogs don't work. I believe there are a few on narrow-gauge and industrial lines.

 

In model form they can work only if all your wheels are exactly the same width, which is not a common situation. Even then the checking function is limited, so even in the US they are restricted to sidings and yards, and other low-speed areas.

 

regards,

 

Martin.

[Glorious NSE]

1. Has anyone built such turnouts in a to scale layout? Do they work well scaled down?

 

I think we've mentioned bits in the US section, they are a bit of a US signature item, i've not noticed any over here...but that doesn't mean they don't exist, maybe in industrial sites there may be some?

 

A working scale version would rely on a specific wheel width as it's the wheel face that prevents the wheel from taking the wrong path at the frog so no need for check rails on the outsides, if you did it you'd need a 'finescale' approach with a consistent wheel standard to make it work, 'standard HO' doesn't work unless you swapped/milled all wheels to the same consistent width (and prevented anyone else from bringing non-compliant stuff!) - and even then the usually too-wide wheels may mean it wouldn't work as well?

 

They obvious work with full sized locos (there aren't many heavier than an SD70ACe). The frog has taken a big ding sometime in it's life. Would they work well at normal operating speeds?

 

You'll find them on low speed trackage only.

 

(Edit - sorry post crossed with Martin's)

[martin_wynne]

Yes Pete, I've seen pictures of some of the latest S & C work with these 'checking' fittings on slips in the UK.

 

Hi John,

 

I think you may be referring to the raised check rails on K-crossings? These are conventional check rails in the sense that they bear on the back of the wheel, not the front. Raising them extends the length over which they are effective.

 

regards,

 

Martin.

[Re6/6]

Hi John,

 

I think you may be referring to the raised check rails on K-crossings? These are conventional check rails in the sense that they bear on the back of the wheel, not the front. Raising them extends the length over which they are effective.

 

regards,

 

Martin.

 

 

I really must look more carefully!

 

Thanks Martin, this is what I was on about!

 

[trisonic]

Thanks, everyone!

 

Best, Pete

[Grovenor]

See http://www.proto87.com/new-products.html

Regards

Keith

[craigwelsh]

Looks like another method of stopping 9Fs getting out on the network if Network Rail had those!