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Hi Rail in the snow pics
Posted by azweig on December 11, 2013 at 2:27 pmDid some Hi Railing yesterday and decided to GPS the line as I was going.
Andy Nold replied 10 years, 10 months ago 6 Members · 11 Replies -
11 Replies
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It’s the Southwest Pennsylvania Railroad under I 70 in New Stanton.
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The last two pics are the SWP under 117 (Brown Street) in Scottdale, PA.
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Rod Height
Just out of curiosity how did you get your rod height for the rover on the top of the truck?
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Rod Height
Funny, looking at that now, it’s the wrong height anyway. But what we did to get the actual height was put the truck on the rail in one of our yards, mark and shoot the rail. Compare elevations of the rail to make sure there was no super elevation, then mount the prism to the mag mount on the roof, pull the truck up so the prism is roughly over the marks we made on the rail. Then we shot the prism and inversed between the rail shots and the prism. I use the vertical difference in the points as the rod height.
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Great pic’s. When you approach a road crossing does your vehicle trigger the warning lights and/or crossing gates?
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No. Our Hi Rail pick ups, 2 F-350’s and a F-550 don’t set them off. We have a Hi Rail rotary dump truck, a Hi Rail prentice truck and a Hi Rail excavator that all do. I was told it’s because the pick ups don’t weigh enough, but I never looked into it any further. We have to stop at all the crossings and wait for them to be clear to go because we do not have the right of way.
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It’s been years ago
But I was doing a survey on property that was on each side of a track at a crossing. We were using a transit and steel tape and as I was pulling the tape across the track the cross arms started coming down. I pulled the tape back and looked down the track – no train. I started across again with the same result. Apparently the signal was triggered when the tape touched both rails. As I said that was years ago and they’ve probably changed the trigger mechanisms by now.
Andy
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Block & Signal Circuits
That is correct. There is a circuit between signal and the two rails. To activate the signal, the wheels and axles of the railcars close the circuit. This is the same way the block signals work (or at least the older system I was familiar with). Maintenance vehicle axles are normally insulated so as not to activate the block signals or the crossing signals. I think I recall seeing a Union Pacific hi-rail SUV that had a switch in the cab that could be used to selectively activate signals.
I rebuilt a Fairmont speeder trailer and helped rebuild a Fairmont speeder. The wheels have a cardboard cone where they attach to the axle to keep from completing the circuit.
Occasionally you’ll see the track joints with an insulating insert at the rail joint and under the fish plates to isolate a block or a signal. Electric railways have a filter box to isolate the lower signal voltage from the traction voltage (trust me when I tell you in spite of 23 years of working on electric railways, I have a limited background on the electric side. Mostly mechanical and track).
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