Trainspotting is a colloquial 80's British term that means "being obsessed with railroad trains" and taking pictures of them. So what does a trainspotter do when there are no trains nearby, he geocaches, of course!
Before McNary Dam backed up the Columbia River thru Wallula Gap, there was a farm and orchard on the river side of the railroad owned by the Thrashers. The railroad curved around the farm on a 90+ degree curve on the cliff side hence the name Thrasher's Curve. Lots of train spotters have take pictures here of trains coming around the curve over the years. Great shots of sunset over the water can also be taken from along the bluff.
The cache is an easy P/G at a wide spot best accessed going west bound. Use extreme caution exiting and reentering the highway as there is a lot of fast moving truck traffic. You do not need to cross the fence. Best to keep the kids and pets inside the car. Cacher assumes all risks looking for this hide.