Lionel scale berkshire minimum radius

You better list exactly which version you mean.

My scale Niagara takes 054 curves just fine.  Unless there's something unusual with a scale Berkshire, it should manage 054 as well.

Fred

Fred Thanks !

My Lionel scale berk went around Atlas 045 just fine.

O54 is fine but looks best on 072 or larger.

Dave

I get mine to take 054 with no problem.

Mine works fine on 048 Fastrack curves and switches.

I have the scale Polar Express - 054 is the minimum and they mean it! I attempted 042, no-go. Derailed almost instantly. 

Apples to Oranges but I've got 3 MTH Premier scale steam locomotives. The first one, a Southern Pacific GS4 4-8-4 Northern, is rated at 054 minimum by MTH. It will run around 054 fine but will also run forward and reverse pulling/pushing a train through 042 curves and switches without derailing. The second, a Santa Fe 3460 class 4-6-4 Hudson, is rated at 042 minimum by MTH. It runs around 042 fine but will not run forward and reverse pulling/pushing a train through 031 curves and switches without derailing. The third, a Santa Fe 5011 class 2-10-4 Texas, is rated at 072 minimum by MTH. It will run around 054 fine but will also run forward and reverse on it's own, at 10 scale mph or less, through 042 curves and switches without derailing. It will not pull/push a train around 042. The biggest surprise was the 2-10-4 being able to slowly go around a 042 curve. I have one in my freight yard and tried it for the heck of it one day and it worked, albeit at very slow speeds. I have Lionel tubular with Ross switches for track.

Your safest bet is to stick with the manufacture's recommended minimum radius, but you can fudge it here or there if you're brave/don't care. The 2-10-4 goes around 054 fine but looks a bit silly doing so, even more so on 042.