It will work fine for most of your needs, with the only possible exception of track power.
Switch machines...hmmm... has anyone ever posted a spreadsheet of current requirements for the many different ones, so that we needn't constantly have these discussions? I suspect that one switch machine, even one of the most robust pre-war Lionel ones, would work fine on one pair of Cat4 wire. If not, since you have already run the wire to that single location, and there are 8 wires in the cable, double them up - twice, even.
A quick rule of wire gauge is this: If you double a wire run (assuming identical gauge for both wires) the resulting gauge equivalent is "three less than one". Example: if you take two runs of #14 wire, and use them in parallel - the resulting equivalent gauge is 14 minus 3, or #11 gauge.
Two runs of #16 gauge is equivalent to 16 minus 3, or #13 gauge. Four runs of #16 would be equivalent to 13 minus 3, or #10 gauge,
Eight parallel runs of #24 is the equivalent of one run of #15, which is adequate for track power. It's between 14 and 16, which are typical track power gauges.
Does the box of wire say 23 gauge? Does it say "copper" or does it say "CCA" somewhere in fine print, which is the industry's trick way of saying "copper-clad aluminum"? Aluminum wire is outlawed for line voltage inside buildings, but is acceptable for large-gauge feeders, and for low-voltage signal wiring, although it does not have the same ampacity as an equivalent gauge of copper wire.
CAVEAT: Even though the calculation method that I have described works in theory, in practice, it is illegal to use parallel conductors to create a larger gauge, if used in a residential or commercial line-voltage (120/240/480) application. So please don't go "trying this at home" (outside the train room.) The NEC prohibits parallel runs to create larger gauges, except for large-gauge feeder applications, in conduit, with the conductors clearly labelled and connected using a particular method.
Google: "Wire Combination Calculator"
