BB confirmed smallest curve

Great information! Thanks for taking the time and interest.

Wish that were done for all locomotives.

Cool that it clears the 175, too bad my 175 leads to my O-54 loop

can you possibly change that loop to 0-63?

But can you run on the outside loop of O72 while the BB is on the inside O63 loop?  I wonder what the spacing for the outside curve has to be to allow the BB on an inside O63 curve.

let me get back to you on this.

Sinclair .............

with atsf santafe #3751 484 on 0-72 curve at narrowest point is 5" center rail to center rail.

BB on 0-63 curve inner loop at same narrow point the clearance is only 13/16" from walkway to walkway of each engine.

at the beginning point of 0-72 and 0-63 curves with a 6 1/2" center rail to center rail  again #3751 on 0-72 curve.

and BB on 0-63 curve.

the clearance is now 2 1/4" from walkway to walkway.

I ran both engines at the narrowest point there was no side swiping or even a hint of it happening.

as a warning if a tunnel is closer than 11" from end of 0-63 curve the BB will in fact remodel the opening for you!!

I know this because I have those exact measurements on my layout it just barely gets the BB boiler straight just in time for the boiler to clear the left hand side of tunnel portal!! so I would not place a tunnel portal closer then 12" from where the curve ends and am thinking 14" would be perfect.

so if one is just at planning stage of layout I would suggest the 6 1/2" center to center rail spacing with 0-72 being the outer loop and 0-63 being the inner loop.

as to a wall or? with 0-72 curves I have a minimum of 5 1/8" from center rail to wall and big boy clears it with room to spare I don't have the exact measurement for that clearance but from memory is no less than 1".

hope this helps any and all here as to this Big Boys needs.

other than a smoke fluid fill feature from its tender man oh man this one makes a drunk look like a slacker !!

 run a scale bb on a 54 or 63 curve...lmao-jim

I tried it through an O60 Fastrack curve, it was no-go.  The locomotive was laboring, the wheels seem to be binding on the flanges.

Much appreciated info from St. Paul.

My still in my mind layout will be a 'shelf' layout with 3 independent concentric tracks.

Now I know that I will need 072 minimum for the Big Boy and now I know the clearances between tracks and wall.

Priceless!

RickM46

Good to know it will make it through the 175 double crossover.

I was wondering about that.

Rod

The question becomes whether it will run on those small curves on a consistent basis, not just 1 time at a certain speed, and what about if there is a turnout right out of the curve. Will it make that tight turn and then make it through a turnout? I doubt it.  The minimum radius Lionel puts out is just that, a consistent basis. Build a train, let it run, and not have to worry about what speed step or slowing down for the curve.

If you want to run it, consistently, and not have to worry about it climbing the rails, then 072 is definitely a minimum.

What kind of consist were you pulling for your experiment?  How did the car right behind the BB act?

Ron

PRRronbh,

here is a video of the 3 boxcars and caboose consist the BB is currently hauling.

none of the cars have any issues tracking behind BB on the 0-63 curves. I was hoping if someone had or could use 0-63 curves on inner loop to be able to possibly gain access to the service/roundhouse and turntable if they so desired to.

i think the video will play as am using my IPad.