Daniel, it would be very hard for me to give you an answer on this. Can you supply a photo? The only saddle tank HOn3 loco that I am familiar with is the old Kemtron "Teakettle" and it was a kit. However, are you quite sure that it will not operate on code 55 rail? Even the old Kemtron loco could operate on the track. If all else fails, how about soldering the rail to printed circuit board ties (explained elsewhere in Freerails) or perhaps gluing the rail to wood ties with contact cement, epoxy, or maybe some ACC (super glue). If you will be hand laying this rail, Micro Engineering makes some super small spikes-"Micro spikes" which are very tiny indeed. I believe that Micro Engineering still makes HOn3 flex track in code 55, turnouts...I just don't know. Good luck, a photo would really be helpful.
____________________ It doesn't matter if you win or lose, its' how you rig the game.