what is the minimum circle radius for my new 4-8-4 niagara steam loco
50301
For best results you should have a minimum radius of 22", for appearances sake I would go with at least 36" radius if not more. But if you are short on space 22" will suffice, I think the tender or first trailing car will come uncoupled on anything lower than 22" if I rememeber correctly.
My 4-8-4 Bachmann runs OK on a 22 but looks oversized for that type layout so I removed it from my official ME&O roster
Here is an overhead pic
As you can see it looks unrealistic
(http://bandb3536.com/north22.jpg)
It's variable due by your tastes.
It's can just barely squeeze by a nineteen inch radius curve. If you do not have secured track, beware! We were running a Niagara around his layout. We had not barely built it, so the track was loose sectional track from Atlas connected by rail joiners. I decided to open the throttle wide around the next corner, and I hadn't seen that the track had move slightly, tightening the curve. The locomotive jumped the curve and fell useless on it's side like a dead rock. No slides, nor any other action. It just plopped off, with a great "Bam!". (The layout was just plywood, painted green.) The domino effect played as the whole consist, connected by couplers, tumbled until the last few cars. About two-thirds of the train was on it's side with almost enough room away from the tracks to allow another train to pass.
So, be careful! I would recommend twenty-one inches in radius and above. If you chose nineteen inch radius, be sure you have just fine curves. However, it's hard to not.
Cheers,
Joshua