A friend of mine, gordon, took these photos at the Amtrak station in Houston showing the new switch that UP put in for the house track where private cars are stored. The wheels ride up and over the other rail on their flanges at walking speed. There is a heavy duty guard rail opposite the frog. Evidently it does not hurt the flange.
It looks like a very narrow diamond to me, but I'm not there. What ever it is, it is interesting. Thanks for sharing Russell. Gary
It does not look like a useable switch any more as there is no guard rail on the other side nor are there any markings indicating any wheels ever rolle over it the hard way. It looks like they bypassed the siding with permanant track for some reason dissabling the switch entirely.
The points are still normal and can be thrown for either direction. The frog has a virtually no maintenance for mainline traffic. I talked to the guy who owns the private cars on that siding and he said his cars have been over it a few times already. It does not need a guard rail on the mainline side as there is no real frog in that direction to worry about.
Here is a UP Genset switcher coming over the switch. You can see the front wheel on the left rise up and cross over the other rail. http://www.youtube.com/watch?v=2zU_-nrTf1g In this video, I was standing in the step well of a private car as we rolled over the frog. I hardly felt anything so did not know when we rolled over the rail head. I was holding my camera out so could not really see what I was photographing but you can see the edge of the "frog" pass under and the wheel bearing housing rise up a little and then drop. http://www.youtube.com/watch?v=4HgM2wlUzbg
Here is the switcher approaching the new turnout. You can see how the ramp raises the wheel up better from this angle.
The photo showing the ramp surte helps clear things up a bit. What a great idea, but why? Would this be reserved for rarely used trackage?
Yes, especially coming off of a very heavily used main line. All the heavy mainline traffic pounding over a conventional frog day after day requires a lot of maintenance. Typically they had to come in a couple times a year with welding equipment and build up the worn frog, then grind the excess metal off to restore the correct shape. Every few years they would totally replace the frog. With the new switch, they predict they may have minor maintenance every five years or so.
I can see the usefulness of this for a spur with little traffic coming off a more heavily-used line. Through traffic doesn't notice anything - it's like going over regular track with no frog at all. Coming off the spur, there's no hurry anyway, so the slight bump can be handled by the suspension in the trucks. I do see a potential for wear on the track itself as the wheels climb over it, but I don't think it would be an issue for very light traffic spurs. They probably thought of that when they designed it, and figured it would take longer for the rail to get damaged than it would take a conventional frog to be worn down. And a small groove is easier to fix than to build up a whole frog. Cool invention!
Before Amtrak picked up the cars last Monday, the UP pulled an SD-40 off the DPU end of a passing freight and used it to spot the cars on the passenger lead for Amtrak. I watched it go over the "jump frog" and it did not appear that the flange touched the rail below it at all. On close inspection after the engine pulled out there were no marks or anything on top of the rail where the flanges had just passed.
Okay, I'm probably wrong about this. It looks like you could only make facing point moves over this switch (frog), there doesn't appear to be a ramp to raise the wheel up to make a trailing points move through this switch. How does that part work?
For a trailing point move, the wheel rolls up to the solid rail. When the flange is a few inches away from making contact with the rail head, the outer part of the tire is wide enough to reach across and make contact with the ramp on the other side of the solid rail. There is only one ramp that the wheel touches and it is on the inside of the mainline rail. The thing on the other side is just a sort of guard rail to push the wheel over so the flange is tight against the diverging rail giving it more contact with the ramp on the other side of the frog. I watched all six wheels of the SD40 go over it and could see it happen. It really does not look like it should work but the geometry is just right and it does.
There are crossings (diamonds) that are similar. The main traffic side rides on flange-bearing ramps, and from what I've been told you can't even tell you've gone over it. The cross traffic side is restricted to 10 MPH and would be a setup similar to this frog.
