Railroad EOT monitors and ACARS

[CommRX]

Railroad end of train monitor chirps sound alot like aircraft acars transmissions. Are they the same? Has anyone tried to decode them? Just wondering since I heard a couple of bursts on my 246 today while waiting for a train to cross the road. I don't live close enough to a railroad to record and decode on the computer, so I was just wondering if they are the same type of transmission.

 

[ironhorse1]

CommRX,

Howdy NC neighbor!!!

Now this sounds interesting... I hope someone will post an answer 'cause I'd like to know too!!

 

[mayor79]

What would there be to want to know? I believe all they transmit back to the locomotives is data on the air pressure at the end of the train.

-Mike

 

[b7spectra]

Actually they also send out a data burst that can be received on other trains to let them know they are in the area. I keep the EOT/FOT (Front of Train) programmed in my scanner so I can tell when one is headed my way!

 

[jlh]

commrx & ironhorse1, another tarheel here. i used to monitor FREDs on the NS line. iirc, they trans brake pressure and motion info, it's a DTMF signal. you can run a DTMF decoder and see the data.

 

[dsw760]

Try out the attached zip files. (Eotmon.zip)
You may or may not need the apigid32 for Eot mon. zip file depending on your computer.

Also have a look at www.atcsmon.com for ATCS, ARES decoding software.

Good luck

 

[wa8pyr]

commrx & ironhorse1, another tarheel here. i used to monitor FREDs on the NS line. iirc, they trans brake pressure and motion info, it's a DTMF signal. you can run a DTMF decoder and see the data.

NS is phasing out these DTMF-based FREDs. Designed in-house by the Norfolk Southern radio shop people, it isn't compatible with the system used by the other North American railroads (which uses ASCII data). After the Conrail merger and ending up with >50% of the CR locomotive fleet, NS started converting their VHF FREDs over to UHF and the standard used by everybody else.

Very few of the VHF FREDs left, at least in my neck of the woods.

Tom WA8PYR

 

[RiP-HS-]

Actually they also send out a data burst that can be received on other trains to let them know they are in the area. I keep the EOT/FOT (Front of Train) programmed in my scanner so I can tell when one is headed my way!

(EOTD= End of Train Device, AKA FRED - F***ing Read End Device)

I'm not sure this is totally accurate. I'm a Freight Train Engineer for a major Railroad and the only thing that goes on between the EOT and the head end device is:

1. Tells the Air Pressure on the rear of train
2. Tells if the rear of train is moving or not
3. Tells the % of the battery in the EOT Device
4. Allows the Engineer to place the rear of train in Emergency from the head end.

As far as I know there is no way to use this information to know that another train is in the area (on a train that is.) On occasion, however, if you are meeting a train and they go by your rear end the EOT will show that the EOT attached to your train is moving. Assuming the reason it does this is the sensor that tell you that your own EOT is moving is picking up his trains movement.
As a Railfan with a scanner it may let you know that a train is approaching because your picking up the signal that is designated for that particular train. But being on a train the only EOT info you pick up is that - that is sent from your own.