BLI Broadway Limited Union Pacific Big Boy 4-8-8-4

This is a BLI "Blue Line" with QSI Revolution and MTH Smoke unit. I swapped out the original sound board and installed the Revolution. The smoke unit runs off the fire box light function, which is synced to the chuff sound. When a real steam locomotive exhausts out the stack, it draws air across the fire box. QSI synced the 'fire box' light to the chuff, so I wired the fan on the smoke unit and run it off the 'Fire Box' function. As a note, the MTH fan/smoke unit will not fit into my PCM Y6b locomotives. I do plan an install into my PRR J1 2-10-4