Korber Models (mr Muffin's trains) makes a fairly easy to build kit for sanding facility including the drying house and bins and the tower. I have the orignal Korber kit. I think it is pretty nice for the steam era. It looks old enough to be appropriate, but modern enough to last into the transition if you want. I built mine and weathered grey.
Another need for a steam facility is an ash pit. Crescent Locomotive Works Inc. has a very nice one that includes a pit and an hoist that he sells built up.
Many of the larger coaling towers also had facilities to load sand into locos. They must have had sand bins somewhere overhead and hoses to do it.
