Fast Tracks

Noticed that some prototypes use a self guarded frog and wanted the forum's feedback/recommendations on how best to model this or if in fact it really makes sense to do it.

I am in N guage so this may also colour everyone's answer.

Modeled self guarding frogs are possible ONLY if ALL the wheel sets have the same wheel profile. This can be a big problem, as many scales (and yes especially N scale) have a very wide variety of wheel profiles installed and marketed by the manufacturers. Even so, the use of self guarded frogs would have to obey the prototype practice of very slow speed operation in yards and secondary traffic routes.

N scale has 9 distinctively and widely marked wheel profiles - most would be incompatible with a single common self guarding frog. HO has at least 3 divergent wheel profiles (and even with all NMRA RP-25 code 110 wheels) there are interface problems.

There are some modeled self guarded frogs - but only in the pure PROTO scales specifications where the tolerance on wheel profiles is very tight. These are small display modules and obey very careful attention to trackwork, speeds, and equipment.

Possible yes - practical; not likely for most modelers.

-ed-

_________________
-ed mccamey-
COSLAR RR - http://www.coslar.us/
NMRA Standards and Conformance Department
PROTO & FINE Scale Coordinator
I estimate I have about 5 pounds of coupler springs somewhere in the vicinity of my workbench.

thank you for the reply and very informative response.

I now completely understand why I will go forward without this specific detail in place

I look forward to continuing this adventure

Can somebody supply me with a picture of a self guarding frog (and what it is supposed to do)

I do not know what they are, being Dutch / Continental. Sounds like something typical for US practice

_________________
Paul Bender

Everybody can shovel, firing is an art


Firing this train was more fun then hard labor © R. de Water

The self guarded frog has lip edges that raise up and contact the face of he wheel and guide the wheel flange properly. There is no guard (or for continental - check) rails.

-ed-

_________________
-ed mccamey-
COSLAR RR - http://www.coslar.us/
NMRA Standards and Conformance Department
PROTO & FINE Scale Coordinator
I estimate I have about 5 pounds of coupler springs somewhere in the vicinity of my workbench.

_________________
Paul Bender

Everybody can shovel, firing is an art


Firing this train was more fun then hard labor © R. de Water

Cheaper (no guard rail and reduced turnout maintenance), relies on only wheel width for checking, the wheel check gauge can be worn or out of specification, and reliable (but slow speed operation is necessary).

-ed-

_________________
-ed mccamey-
COSLAR RR - http://www.coslar.us/
NMRA Standards and Conformance Department
PROTO & FINE Scale Coordinator
I estimate I have about 5 pounds of coupler springs somewhere in the vicinity of my workbench.

Not sure if you all caught this:

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

Self-guarded frogs coming soon! I assume you'll be able to build up the Fast Tracks turnout, but leave the frog out, and then splice in their frog casting. I'll have to test it when they come out...