Databursts on BNSF Road Channel

N9JIG · Oct 30, 2018

I am hearing short databursts on the local BNSF Road channel: 161.370 on the Phoenix Sub some 40 miles NW of downtown Phoenix (Timetable east).

Usually I hear other radio traffic before or after pertaining to a passing train (detectors, warrants etc.) but are not part of a communications, they are just independant transmissions.

These databursts sound sort of like EOT data but obviously are not. They are shorter in duration, fractions of a second. They are not MDC codes and due to the very short duration are not some sort of digital voice.

I have only started hearing them recently over the last week or so but that doesn't mean they weren't there before. I almost always have a radio on this channel, in the truck and at home and this is the first time I am hearing this.

Any ideas? I am thinking perhaps some sort of remote activation of a switch or acknowledgment of a clear slide detector etc.I am 9 air miles from a 2-way siding and 11 miles from a 7000 foot siding.

N9JIG · Oct 31, 2018

I got a recording of this via the 536's Replay function:

https://www.dropbox.com/s/4qr79whkuxpeorz/2018-10-31_07-18-20.wav?dl=0

phask · Oct 31, 2018

Is distributed power done via radio? I have no idea.

N9JIG · Oct 31, 2018

DPU's are usually on 452.9xxx/457.9xxx. I have never heard of them being used on the Road channel. Same with ATCS.

Railham_CJ · Nov 12, 2018

PTC related ?

N9JIG · Nov 12, 2018

Could be PTC I suppose. The BN side of the BNSF used VHF for ARES but they never used the local Road channel for it.

I suppose it could also be from outside the area if conditions were ripe but I have not noticed any weird band openings recently around here.

kruser · Nov 13, 2018

N9JIG said:
Could be PTC I suppose. The BN side of the BNSF used VHF for ARES but they never used the local Road channel for it.

I suppose it could also be from outside the area if conditions were ripe but I have not noticed any weird band openings recently around here.

They still use a couple AAR VHF channels for ARES but the sample sound supplied here does not sound like ARES data when I compare it with the BNSF ARES sound I can hear on AAR07 here. ARES was my first thought as it is widely used here but like you said, not on the actual road channel.

JoshuaHufford · Nov 13, 2018

I agree, that does not sound like ARES data, and it would be very odd for ARES data to be on the road channel.

K2RNI · Nov 14, 2018

N9JIG said:
DPU's are usually on 452.9xxx/457.9xxx. I have never heard of them being used on the Road channel. Same with ATCS.

I'm in Seligman Subdivision and I have actually quite regularly heard them on the VHF side. No idea why, I just figured it was normal out here.

N9JIG · Nov 14, 2018

Many years ago a friend who was tight with the WC was asked to help them track down a wayward signal on the WC Road channel (161.295) emanating from someplace north of Chicago and south of Milwaukee. It was making the channel quite unusable and really disrupted operations.

He and I started DFing the signal and in a couple hours tracked it down to the Soo Line's ex Milwaukee Road Bensenville Yard on the Milwaukee Rd. We eventually found it coming from a CP MLW locomotive in the ready line, which was equipped with a shut-down alerter that sent out beeps on whatever channel the locomotive radio was set to, in this case that radio was set to Channel 79, the WC Road channel. Why the radio was set to that channel is unknown as the locomotive had come in on the Toronto train that morning as a trailing unit. When they shut it down the alerter went off and since the Soo at the time did not use Channel 79 they never heard it.

This is a long way too say that it could be something transitory and I may never know what caused it. I have not heard the beeps on the BNSF Channel 84 the last couple of days and was out of town for a few days as well.

N9JIG · Nov 14, 2018

Well, the data is still there so it is probably not related to conditions.

N9JIG · Nov 17, 2018

I wonder now if it isn't some sort of dispatcher call-in answer-back. A couple times now I have heard the data followed shortly by the dispatcher answering back. I haven't heard the train call-in though, it must be too far away.

N9JIG · Nov 17, 2018

Confirmed, Dispatcher Answerback

I went out today lineside and verified that it is almost certainly the dispatcher answerback. Where I live is hard to hear the trains when they dial up the dispatcher to obtain and release warrants but I can hear the dispatchers. I was finally able to hear a train dial up the dispatcher with the DTMF codes a couple times and each time the databurst popped up a couple seconds later, before the dispatcher answered. Since the dispatcher doesn't always immediately answer the dial-up it wasn't apparent that they were related until I could get closer in and hear everything.

They used to use a standard (1000 Hz.?) tone but seem to have changed it to a small databurst, at least here on the Phoenix Sub's west end. Next week if I end up going up towards Skull Valley I will see if the towers there also have the same sounds.

RadioDitch · Nov 18, 2018

Just a system acknowledgement indicating that base which was toned up received the DTMF tones and lit up the call alert on the dispatcher's console.

DaveNF2G · Nov 19, 2018

I am observing the same system (answerback) in use by CSX near the Selkirk (NY) Yard, where their regional dispatchers used to be located. Now they bring up the Feura Bush transmitter from Jacksonville.

N9JIG · Nov 19, 2018

RadioDitch said:
Just a system acknowledgement indicating that base which was toned up received the DTMF tones and lit up the call alert on the dispatcher's console.

Answer-back is pretty common but this is the first time I have ever heard a databurst instead of just a plain tone, on BNSF or other road.

Almost sounds like a shorter version of MDC (which used to be commonly heard on BN locomotive radios) but my MDC decoder does not decode it.

I don't know if the data itself has a purpose other than as a sound source or if it is just used on the particular base radio in this area. The one I hear is likely the Wittman AZ base on the Phoenix Sub. I wasn't able to head north this weekend to Skull Valley like I had hoped but if I do next weekend I will try and listen for it off the other bases on the sub.

marlin39a · Dec 5, 2018

I'm at MM 33.5 (Paulden) on the Peavine, Phoenix Sub. I monitor daily, and have not heard anything out of the ordinary here. Plenty of Track Warrants from Williams Junction to Williamson Valley. I have Abra, 5 miles up the road. There is a siding there for trains to pass. 161.370 is very active.

N9JIG · Dec 5, 2018

marlin39a said:
I'm at MM 33.5 (Paulden) on the Peavine, Phoenix Sub. I monitor daily, and have not heard anything out of the ordinary here. Plenty of Track Warrants from Williams Junction to Williamson Valley. I have Abra, 5 miles up the road. There is a siding there for trains to pass. 161.370 is very active.

I think it was just one dispatcher tower around Wittman that was doing this, I was in town a few days ago and the tower close to El Mirage had the standard tone.

shotguns7 · Jan 14, 2019

Could it possibly be the end-of-train telemetry device? That’s my best guess....

Joe. 30 yrs on Norfolk Southern

JoshuaHufford · Jan 14, 2019

shotguns7 said:
Could it possibly be the end-of-train telemetry device? That’s my best guess....

Joe. 30 yrs on Norfolk Southern

Those are usually in the UHF range. 4xxMHz something, don't remember off the top of my head.

Databursts on BNSF Road Channel

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