I would not buy Atlas turnouts, but that is strictly a personal preference. In the modular club we have a number of modules that have Atlas Custom Line turnouts installed on them that operate without any problems. The purpose of the flangeway is to keep the train from derailing as it goes through the turnout. Being a little tight is not as big a problem as being too loose, which would allow the wheels to drop off the track onto the ties. Have you used the gauge to check the wheel spacing on your Big Boy, reefer, and MP15ac? Also how much side to side "slop" is there when one of you problem pieces of rolling stock is parked on the turnout? We have had a few problems with Atlas Custom Line code 100 turnouts at the modular club with flangeways being too wide to work properly, even when the NMRA gauge fit. What members have done is glued a thin strip of .015 styrene to the inside of the flangeway to tighten them up slightly. Essentially, rolling stock tends to drop into the ties toward the moveable points in the turnouts, so the flangeways are designed to hold the wheels close to the solid rail. You might push the reefer that has a problem through the turnout with another car as a handle so that your hand doesn't change the cars behavior on the turnout. As you push the reefer that has a problem through the turnout, what does the car do? I think it will do one of three things. If everything is ok, it will go through smoothly. If the flangeway is too loose, it my try to drop off the rails. If the flangeway is too tight, or too shallow, it may ride up above the rails either riding on the flange in the bottom of the flangeway, or because the tapered flange is squeezed by the flangeway causing it to ride up. If you can see exactly what is happening, then you have a better chance to fix the problem. Also while you push the car through, check it's behavior as it goes through the frog as well.