What remains seems to be where some large timbers were bolted down that might have supported pit rails, just an educated guess. Did the SP use elevated pit tracks? Have any pics of the engine house structures turned up? Looks like a single track. If the pit was elevated, one would assume that it was a quickly built structure, maybe temporary. One would probably dig a permanent pit for an engine house I think...not sure if there is an improved brick pit under grade level. Have to look next trip. Maybe the bricks were part of the pit?