Cache actually has nothing to do with yaks or yuletide except the train was decked out with Christmas lights when cache was placed. Other times of the year it wears ducks and/or beaver colors. The engine is a 1904 Baldwin steam locomotive and was built in Philadelphia and used in mining in Mexico until 1960. It returned to the US and was in use until bought by collectors in 1991. Legend has it that Pancho Villa actually road in the engine's cab during the Mexican revolution. The engine came to Keizer Station in 2009.
Look carefully and you will find the cache an easy reach from outside the fence. Cache is log only so bring a writing stick. Cache is not green or plastic.