I kinda like the thought of having trouble lifting the engine; traction .
Hhhm...NMRA scale weight ? 😲
Could it be run upside-down like some of Dale M.s ? 🙃
I have a couple (weak) barrels somewhere.
I have a block of regular magnet and use it by hand. The tracks aren't inaccessible. I like to drag things towards the outside edges of the ties first.
I always just used some kind of tape to "vacuum" metal from magnets.
You can also use tape as a removable protective "catch layer" by putting tape over one before you sweep. After, wrap more tape over splinters to capture them, then cut and peel away the tape like an onion skin.