minimum switch frog radius number for 4-8-4?

[pdx650]

What is the minimum frog number for a 4-8-4? I think a #4 frog turns into an 18" radius turn, but can the #4 frog on a switch be used safely (without derailments) on a 4-8-4? Or should I go up to a #6 for a good rule of thumb for minimum frog number? anybody?

 

[FunValleyLine]

I have several 0-8-0s, 2-8-4s, 2-10-2s all Rivarossi that run 4s and 6s fine. The 611 Bachmann 4-8-4 does fine. My 2-8-8-2 does ok at slow speed but usually lifting the front truck is best. Good Luck, Tom

 

[pdx650]

thanks for the reply.... Also, I know my bachmann daylight 4-8-4 (5449), can not do an 18" radius curve. Question is as long as I make the turn after the number 4 switch into a 22" minmum turn...will the 484 still make that #4 successful?

 

[HaggisKennedy]

My Proto 2-8-8-2 makes it OK, but I'm not blasting through at speed. My 2-8-4 also makes it OK.

These are Atlas #4s.

Kennedy

 

[stokesda]

Keep in mind the Atlas #4's are actually #4.5's, and so are not as sharp a turn as an actual #4. So a loco that can make it through an Atlas #4 won't necessarily make it through a #4 from a different manufacturer.

For what it's worth, I have a Bowser 4-8-4 that can negotiate an Atlas #4 - at slow speed, and not very happily, but it will make it. My Spectrum 4-8-2 doesn't seem to have any problems.

 

[FunValleyLine]

Only thing I know to do is lay it out on a temporary board and try it. None of mine have trouble on an 18 at slow speed though they look yucky.

 

[conrail92]

I would go with a #6 it will look better and function better, Less likely for a derailments and you can go over them quick with no worries.

 

[pdx650]

thank you for all your helpful responses!