I also tried an active subwoofer instead of the low-pass filter.
For my ears I can achieve a better result for the loco sound when I’m able to regulate the frequency,
down to a lower bandwidth than the subwoofer electronic is able to.
But the active subwoofer / satellites combination is great for an ambience Harbour sound,
I recently got from Fantasonics.
____________________ modelling in 1:22.5 on 32mm and 16.5mm track
Actual project: 7/8" scale on 45 mm track