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Western Railroad Discussion > Q. Electrocode

Date: 05/08/03 20:41
Q. Electrocode
Author: .007

Perhaps Xingman or sombody else could take time to explain what this is and how it works. Or if there is a good site, I would take that.

Does this represent a reasonably modern upgrade as things go?


Date: 05/09/03 06:57
Re: Q. Electrocode
Author: richmp412

Probly wont be much help on this but here is what little I know about electrocode. Others can correct my errors. In our area BNSF Transcon east of KC, Mo. electrocode is the latest thing being installed. NS has had it for a few years and BNSF has it from Congo to Mo. River bridge in Missouri.
With electrocode they put all info into the rails by way of electric impluses or codes, no longer needing the wires on a pole line along side the tracks, ie no more pole line. The information is handled electronicaly by wayside equipment to indicate train movement between signals also sets up direction of traffic after the ds lines a train into an area between CTC stations. I know this is very basic but it does everything the old relay and land poleline wire used to do. As far as I know it works very good.
Xingman HELP :-).

Date: 05/09/03 07:11
Re: Q. Electrocode
Author: rfdatalink

I belive Electrocode is actually a name brand for what is generically a Coded Track Circuit. This means that instead of just putting DC voltage across the rails to detect a train, the signal equipment sends a message from one end to the next. This signal is much like someone tapping out morse code. By doing this they can eliminate the need to have a circuit on the pole line from one signal to the next.
Depending on the make of equipment, and how good the track is, a coded track circuit is only good for about 6000 to 10000 feet before the signal fades away. It is good for communications from one signal to the next, but does not work for dispatcher to CTC control point communicatioins. That is usually done with RF codeline or some other replacement for the pole line.
I belive coded track circuits have been in use for 20 to 30 years, but are the "state of the art" today.

Date: 05/09/03 08:20
Re: Q. Electrocode
Author: Xingman

Both replies are correct. The only thing I would change is that we have electrocode blocks that are over three miles long. So they can be used to go farther than 10,000 feet.

Electrocode is the name of the equipment that generates and receive the coded track circuits and is made by GE Transportation Services (previously Harmon). There are other manufacturers that have the same type of equipment that is called something different like Genracode, etc.

The aspect displayed on a particular signal is interpreted by the amount of time between pulses. If no pulses are received because of an open track circuit or shorted track circuit (usually a train shorting the rails out), the equipment will supply power to the necessary lamps to display a stop indication. Each lamp is also powered by the electrocode unit.

Not only does electrocode eliminate the need for pole line, but it eliminates alot of relays which have to be tested regularly, therefore eliminating alot of maintenance requirements.

Just think, you can take pictures without worrying about that pesky pole line being in the way.

Hope this helps,

Date: 05/09/03 11:53
Re: Q. Electrocode Question
Author: tcnr

Wouldn't this allow for signals in the cab of the train on the circuit? Although it sounds like it would not be updated instantaniously.
Great that they've gone to all that trouble to remove those pesky poles for photographers.

Date: 05/09/03 12:26
Re: Q. Electrocode Question
Author: rfdatalink

No. The only sections of track that don't have the codes being transmitted through them are the ones that are occupied. The wheels of the train short out the rails so no codes can be transmitted.
Obviously this is exactly the opposite of what you would want for cab signals.

Date: 05/09/03 14:42
Re: Q. Electrocode Question
Author: tcnr

Thanks for the clarification, rather obvious when there's a 10,000 ton train causing a low impedance between the rails.
Certainly limits the functionality, I guess they have to pick up the info before and after the train passes, kinda like a moving black out of information. Now maybe I can sell them a Geo-Sync Satellite for something like that!

Date: 05/09/03 16:19
Re: Q. Electrocode Question
Author: run8

rfdatalink wrote:

> No. The only sections of track that don't have the codes
> being transmitted through them are the ones that are occupied.
> The wheels of the train short out the rails so no codes can be
> transmitted.
> Obviously this is exactly the opposite of what you would
> want for cab signals.

That is exactly how cab signals work, however. The wheels of the locomotive shunt the track circuit, so the coded signal passes down one rail, is passed to the other rail through the leading wheelset of the locomotive. Inductive pickup coils mounted in front of the wheels, just above the rails, pick up the coded signal and pass it to the cab signal equipment.

As I recall, only minor modifications need to be made to the electrocode system to take advantage of cab signals.

Date: 05/09/03 18:24
Re: Q. Electrocode Question
Author: Xingman

I have never dealt with cab signals, but rfdatalink sounds dead on to me.


Date: 05/10/03 01:40
Re: Q. Electrocode Question
Author: csxt4617

what kind of code system uses 1 pair of line-side
wires? That's the kind of system CSX uses here.
Of course, everytime the wind blows in any kind
of storm, the code line goes down, and it's
time for the crews to hand throw the switches and
get talked by red signals ;^)

Date: 05/10/03 04:14
Re: Q. Electrocode Question
Author: run8

Xingman wrote:

> I have never dealt with cab signals, but rfdatalink sounds
> dead on to me.

Here's a link to descriptions of the Electrocode and Genrakode versions of microprocessor-based track circuits. They include descriptions of the cab signal add-on.


Cab signalling uses a specific set of coded AC signals (typically 100 Hz) sent down the rails, which are then detected by the on-board equipment on a locomotive. In principle, it is very similar in concept to how Electrocode exchanges vital aspect information to control the wayside signals, so the adaptation for a specific set of cab signaling codes is straight-forward. Instead of transmitting the information to the next Electrocode unit, it is intercepted by a locomotives's on-board equipment.

Here is a link to the Electrocode cab signal modules, which have a short, inadequate, description of how they work:


Date: 05/10/03 08:07
Re: Q. Electrocode Question
Author: Xingman

Oops! I'm sorry, I said rfdatalink sounded dead on, but I meant run8 sounded dead on. I saw rfdatalink's name in run8's post and turned them around. Sorry for the confusion.


Date: 05/10/03 14:12
Re: Xingman long blocks
Author: AAK

How long is your longest track coded block?

Around here we have only a few blocks that are longer than 2.2 miles and all of those longer blocks have code repeaters approximately midway.

Date: 05/11/03 09:39
Re: Xingman long blocks
Author: Xingman

3.5 miles is our longest block and we haven't installed any repeaters.


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