Isolating a section of already-ballasted track?

[Steamtrains]

Rob: you may have to use the cutters twice, once in each direction, to both get a smooth cut on both faces and to have a bit of a gap.
You will probably want to file the running surfaces afterwards, anyway.
Don't use them on anything other than rails or small copper wire. Guitar strings, switch machine rods will notch the blades.

So true....I put a couple of knicks on the cutting edges of mine when I cut some thin piano wire for my switch machines.....