I've see a prototype photo of a winch on the front of a Hiesler and ON30 kits to put them on Shays. Where would a steam line for powering a winch be plumbed to the locomitve. Just drilled and tapped onto the top of the boiler?
It would be into the steam dome (not just anywhere on the top of the boiler). Actually, it most likely would come from a steam manifold in the cab, usually near the top center of the boiler backhead along with a hand valve to control the admission of steam to a second valve at the winch, the manifold being fed from a connection to the main steam dome or a secondary one, possibly in the cab area.