made a mistake , reply with out seeing 8 ohm resistor instead of 6 ohm resistor. thanks.
No, that 5V regulator is NOT the smoke regulator. You do NOT want a 6 ohm resistor, you want an 8 ohm resistor. Ignore the parts list, that was a problem and Lionel changed to the 8 ohm resistor.
I'd like to know for sure what you actually have. I'm looking at the Legacy with whistle smoke, and it uses the dual smoke unit.
First step is to actually know what you have, I think I'm shooting in the dark here! 
You are correct, its two smoke stacks, with some sort of 1 in to two situation. I have not yet tested the lead for voltage. I assume i purchase a 8 ohm resister dumping the 27 ohm resister in the replacement smoke unit 640-8057-200 , is there anything down stream of this unit I have to add, have to follow this lead and check if possible for the part 691sfc1101 # 96 on the lionel parts list " PCB smoke fan control and see if its missing too. and yes i would need 6101208201 smoke funnel #97 and 691res80hm 8 ohm resistor #98 Thanks.
