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Positive Train Control and satellite VSAT terminals

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Positive Train Control and satellite VSAT terminals
Posted by aegrotatio on Wednesday, March 15, 2017 11:33 PM

I was involved with bidding for telecommunications infrastructure for PTC on a Class 1 railroad about 8 or so years ago.

 

VSAT terminals operate in Ka- and Ku-band, both of which suffer from "rain fade."  Since my other hobby/profession is/was satellite disk installations, I naturally asked what happens when communications are lost to a railroad block.

 

They said they drop all signals to danger.  Essentially, the railroad randomly shuts down during storms.

 

With this, I'm asking any of you if you know how (or if) the industry has overcome this?  Is VSAT only a backup to another terrestrial technology like cable, radio, or mobile phone data?

 

 

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Posted by BaltACD on Thursday, March 16, 2017 8:32 AM

aegrotatio
I was involved with bidding for telecommunications infrastructure for PTC on a Class 1 railroad about 8 or so years ago.

VSAT terminals operate in Ka- and Ku-band, both of which suffer from "rain fade."  Since my other hobby/profession is/was satellite disk installations, I naturally asked what happens when communications are lost to a railroad block.

They said they drop all signals to danger.  Essentially, the railroad randomly shuts down during storms.

With this, I'm asking any of you if you know how (or if) the industry has overcome this?  Is VSAT only a backup to another terrestrial technology like cable, radio, or mobile phone data?

PTC being implemented on the Class 1's is a OVERLAY system and it is on top of the existing Automatic Block Signal of the carriers.  The operation of the 'brick & mortar' signal system detirmines what information PTC needs to convey to trains. 

Learning what happens during periods of inclement weather is part of the real world testing that is currently taking place as PTC is being incrementally installed across the Class 1's.

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Posted by Buslist on Thursday, March 16, 2017 9:38 AM

aegrotatio

I was involved with bidding for telecommunications infrastructure for PTC on a Class 1 railroad about 8 or so years ago.

 

VSAT terminals operate in Ka- and Ku-band, both of which suffer from "rain fade."  Since my other hobby/profession is/was satellite disk installations, I naturally asked what happens when communications are lost to a railroad block.

 

They said they drop all signals to danger.  Essentially, the railroad randomly shuts down during storms.

 

With this, I'm asking any of you if you know how (or if) the industry has overcome this?  Is VSAT only a backup to another terrestrial technology like cable, radio, or mobile phone data?

 

 

 

The basic communications for PTC is via 220MH radio, hence all the discussion of spectrum availability. The only satalite links involved are for GPS location determination, and there are several redundant backups.

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Posted by tree68 on Thursday, March 16, 2017 12:10 PM

Buslist
The basic communications for PTC is via 220MH radio, hence all the discussion of spectrum availability. The only satalite links involved are for GPS location determination, and there are several redundant backups.

I see an awful lot of new shelters with satellites dishes on them.  And I'm pretty sure that when the North Baltimore intermodal facility was "cut in" to the CSX main, that area disappeared from the traditional ATCS screens, in favor of a satellite connection.

LarryWhistling
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Posted by Buslist on Thursday, March 16, 2017 3:54 PM

tree68

 

 
Buslist
The basic communications for PTC is via 220MH radio, hence all the discussion of spectrum availability. The only satalite links involved are for GPS location determination, and there are several redundant backups.

 

I see an awful lot of new shelters with satellites dishes on them.  And I'm pretty sure that when the North Baltimore intermodal facility was "cut in" to the CSX main, that area disappeared from the traditional ATCS screens, in favor of a satellite connection.

 

Seperate issue from PTC but use of satellites for code line is becoming common replacing the 900 MH spectrum.

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Posted by samfp1943 on Thursday, March 16, 2017 6:50 PM

tree68
 
Buslist
The basic communications for PTC is via 220MH radio, hence all the discussion of spectrum availability. The only satalite links involved are for GPS location determination, and there are several redundant backups.

 

I see an awful lot of new shelters with satellites dishes on them.  And I'm pretty sure that when the North Baltimore intermodal facility was "cut in" to the CSX main, that area disappeared from the traditional ATCS screens, in favor of a satellite connection.

 

              "Satelite Dishes"(?)  Is this a new wrinkle to the PTC installations? About 18 mos or so, ago. BNSF came through this area (Wichita and Wellington) installed fibre-optic cables, and most of the " signal bungalows' were changed, and at each area of 'control' there were radio antennas installed.       Nothing out of the ordinary, just added tall poles masts (about 20' ,or so); some had just a di-pole style antenna, and some had the single antenna with addition of a flat,oval loop on the antenna. 

            Have not seen any of the dish style antenna   on any of the BNSF bungalows, around here .         UPRR, at about the same time, did a heavy maintenance cycle on their line south of Wichita(The OKT sub) on what was the former RI ROW.        UPRR did not seem to change their signaling equipment, or externally, change their signal bungalows(?) at that time . I have noted that many of the BNSF locomotives, have been equipped with a creme colored, low plastic(fibergalass?) housing in the center of their cabs; I had just assumed it was to house the unit's radio antenna(?). 

Sam

 

 


 

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Posted by blue streak 1 on Thursday, March 16, 2017 9:40 PM

On the CSX A&WP sub it has had ATCS installed at each siding.  Now in the past 2 weeks there are satelite dishes being installed at each intermediate signal.  There is a lot of tree clearing being done at each site.  Dishes do not appear to be operational yet.  Have not checked other CPs but am planning to  next week.

Edit have only seen one site with a telephone line.

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Posted by tree68 on Friday, March 17, 2017 6:44 AM

Buslist
Seperate issue from PTC but use of satellites for code line is becoming common replacing the 900 MH spectrum.

No code line to replace on this particular line - all dark territory....

LarryWhistling
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Posted by rfdatalink on Thursday, March 23, 2017 3:53 PM

Some railroads favor satellite more than others.    CSX seems to really like it, but UP and BNSF not so much.  In most cases these communications paths will be used for codelne possibly PTC communications back to the back office.    The railroads will generally try to have at least 2 communications paths availible. If they have satellite then they may have cell or DSL as the backup.    Cell is a common backup because tends to get expensive to move much data over cell, but there is very little cost to having the cell modem standing by.

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