Great Northern Atlantic

[modelsof1900]

The ropes to bell and whistle were made out of 0,3mm soft brass wire. Yes 1900, i know you do not like this stuff, but here in this case it is the right material.
If it is too thick, it is no problem to pull it thinner as i have done it.

Lutz, yes, you are right.
However look for different electrical cables. They all are made from thin copper wires with diameters far under 0.3mm (.12") and this will be a better choice. Good luck!