I’m considering using Atlas code 100 track for the staging areas of my layout, since it’s plentiful, relatively inexpensive, and–from what I understand–reliable. Appearance doesn’t matter, since this is hidden staging. However, I have one concern: I have read in a few places that Atlas track is guaged slightly wider than, say, Micro Engineering track. If true, has this caused any issues/problems/repeated derailments for those using semi-scale (.088) wheels?
Thanks in advance for your help and insights.
Unless the track is gauged wider than NMRA specs, properly gauged wheels - even code 88 wheels - should have no problems. Proto87 wheels, being even narrower (about .064"), have to limit the gauge widening to less than the full NMRA tolerance so that the wheel doesn’t drop inside the railhead.
The kicker is in the turnouts. To guarantee proper wheel support throughout the frog area, tread width should be at least 2X the flangeway width. NMRA-spec flangeways can be from 0.040" to 0.050". Code 110 wheels (normal HO) will work with the entire range. Code 88 wheels need the flangeways to be on the narrower side to avoid wheel drop or rattle during transit through the frog. To use the 0.040" flangeway, track gauge must be at NMRA minimum in the frog area, otherwise the check gauge won’t be right. Very few commercial turnouts meet the min track gauge/min flangeway spec - keeping the track gauge at minimum in the curved sections drives up minimum radius requirements. Note that if the frog is straight, there is no reason why the gauge can’t be widened slightly in the closure rail area to allow the sharper minimum radius and narrowed to minimum at the frog for the code 88 wheels.
That said, the inability to fully support the wheel tread through the frog does not necessarily mean derailment city. Some manufacturers (and hand-layers) fill the flangeway so that the wheel can ride on its flange if need be. Others (Fast Tracks) use a very sharp frog point to extend the frog point into the throat and effectively narrow the flangeway in the critical area. Even without these “features”, the typical code 88 wheelset will usually drop slightly and make a little noise while in the frog on a typical commercial turnout, but will not derail. Wheel drop gets worse as the frog number get bigger - ironically, the more realistic appearing #8 may give derailment problems where a
It could be the Atlas track’s gauge isn’t wider, but that the rails themselves are wider. I know Atlas code 83 track is noticeably wider than Kato Unitrack code 83 for example.