Sand House

The next addition to the engine service facility was the sand house.  I'd seen plenty of models of sand houses, most of them based on the ones at Durango or Chama.  Basically they consist of a large sand bin that gets loaded by hand from a gondola and a one story structure with no windows.  Next to the sand house is a large tower with a spout for loading the sand into the sand dome of a locomotive.  It took some serious research to find out what was inside the sand house and how everything worked together.  Here's what I learned;

Sand gets delivered to the sand house on the raised service track (Chama) that runs behind the coaling tower.  It gets unloaded by hand into the sand bin which is located against the side of the sand house.  There's a doorway from the house to the bin and a hatch in the wall at about chest height.  The sand gets shoveled through the hatch and lands in a smaller bin inside the sand house.  Next to this bin is a coal fired furnace with a stack extending up through the roof.  Around the top of the furnace is a plywood bin shaped like a large funnel with numerous holes (about 1") punched in the plywood.  Sand gets shoveled into this funnel and the heat from the furnace dries the sand, causing it to sift through the holes and fall to the floor.  The dried sand then gets shoveled into another small bin.  This is located against the wall with the sand tower just on the other side.  There's a pipe that runs from the front of the building, forms a "Y" at the bin and then extends to a holding tank at the top of the tower.   When an engine pulls up to get sand they connect an air hose from the locomotives compressor to the pipe at the front of the sand house.  The force of the air going up the pipe draws sand through the "Y" connection and pumps it up to the tank at the top of the tower.  The air exhausts out of the tank through a pipe at the top and the sand falls into the tank.  The bottom of this tank is funnel shaped with a valve at the bottom.  The spout is attached to the funnel by a hinge so it can be raised and lowered.  There's a handle on the end of the spout that connects to the valve.  The fireman opens the lid if the dome and lowers the spout.  When it's in position he pulls on the handle to open the valve and sand is gravity fed down through the spout.  But wait, there's more.  The roof of the Chama sand house has two vents in it.  The heat from the furnace rises to the rafters and gets exhausted through the vents.  There are no windows because they're trying to keep everything warm and dry inside.  If the sand is wet when it gets forced up to the tower it can clog the lines of both the tower and the locomotive.  It's gotta be dry.  Once it's in the sand dome of the locomotive it's kept dry by the heat of the steam running through the tubes inside the engine.  That's why the sand dome is on top of the engine.

When I built the coaling tower I decided the back side of the engine service facility should be visible from the side of the layout because it has more visual interest.  I wanted to add some plausible detail to the sand house too.  This is where I let my mind wander.  That gondola is sitting up on the service track 5' above the sand bin.  That same track is used to dump coal into the coaling tower bin from a hopper.  Why not use a hopper to deliver the sand too and have the sand bin extend under the service track just like the coal bin?  The sand still has to be shoveled by hand into the sand house but it just made sense to me that it should be built like that.  I also thought the sand bin should have a roof at the house end to help keep the sand dry.  Beneath the track the bin is divided in two with the right side used for coal.  Everything else is based on the sand houses of Durango and Chama.  The sand house and raised service track are from Chama.  The sand tower at Durango had a better look to it so I used that.

For the sand tank at the top of the tower I used half of a plastic "hour glass" style timer from an old board game.  I ran heavy thread through the air line to the weight on the counter balance to give animation to the spout.  The tread runs into the sand house to a stepper motor mounted beneath the layout.  Control is by an Arduino which also provides a sound track for the sand house.