Alpine Tunnel rail joint

I finally bounced all the way up to the west portal of the Alpine Tunnel the other weekend, after only seven years of living out here. About time, I figure...
One of those oddities I photographed was this bizarre old rail joiner. It wasn't just this one - there were quite a few throughout the restored trackwork. I even remember asking the USFS volunteer up there, and he mentioned it by some name. Unfortunately, I think it rattled out of my brain by the time I got down to the bottom, as by now all I can draw is a blank. I spent part of today going through the USPTO's patent database, but couldn't come up with anything that looked quite like this.
I'm hoping somebody here can help me out with the name... Also, how common were these? I assume they were from the early construction of the South Park, and gave way to regular joint bars in time?