I broke out the Starrett digital calipers to measure the old and new BLMA wheels, total wheel width including the flange. The old ones, from the run G31 gons 33" measures in at 0.054", the new from a PS4000 covered hopper 36" measure in at 0.065". (I also measured them with a set of dial calipers and came out with the same results.) I think that the wheel widths are the same on all diameters, the difference is from the time they were produced. On my almost 20 year old layout, code 80, the PS4000 has no troubles at all holding the rails, half of the gons I have will pick points randomly, and even derail on a straight piece of track for no obvious reason. I think it might also have to do with some of the trucks not being free enough on the kingpins for even tracking. Measuring some other metal wheels: Fox Valley 33" 0.066" , Atlas 33" 0.066", and from an ESM X58 0.054" (hasn't had any problems with derailing or picking points). I don't have any FVM wide wheels to measure, yet.
As soon as I get the body-mount couplers installed, I'm going to try the 36" BLMA's on some Athearn coalporters. They're substantially more weighted than the E&C ones (I just discovered last night that they have four weights instead of the usual two), so we'll see if extra car weight helps eliminate derailments.
Please keep us posted on your findings, Chris. There is always a physical reason why derailments happen, and it's now a matter of finding out exactly why. I would definitely check the wheel and track gauge on trouble areas. We have re-designed our wheels as noted. Newer production models and wheels will have a slightly taller flange and tread width. Furthermore, we've done extensive testing on layouts all over Southern California without issue. Here is a video two long trains at the East Valley Lines club layout. Both trains have either 33" or 36" BLMA wheels, depending on the models: http://youtu.be/xK5ZobDhA8g
I decided to give the BLMA 36" wheels another try, with better success this time. The problem may very well have been that I was running the trains on less-than-optimal track; this time I went out of my way to make sure there weren't any kinks in the rails, and so far no derailments. But I also converted the MT couplers into "Micro-Mates" by putting Accumates into the 1035 coupler boxes, in order to get rid of the slinky effect. All the bopping back and forth might have contributed to the wheels jumping the rails as well. Looks like I'll be able to use these nice looking wheels after all
