Track circuit fault

[Adam morrison]

Can anybody walk me through the step by step on what you’d do if you came to a low voltage track circuit fault. Thanks in advance

 

[Railsigns]

My actions would largely depend on what my role was (driver or S&T technician, etc.).

 

[Annetts key]

Can anybody walk me through the step by step on what you’d do if you came to a low voltage track circuit fault. Thanks in advance

This sounds very much like an examination question.

 

[Islineclear3_1]

Can anybody walk me through the step by step on what you’d do if you came to a low voltage track circuit fault. Thanks in advance

Do you work for the railway? Are you a signaller or NR employee?

Could be any number of things causing the fault.

What is your job role at the moment? Have you any experience of working with track circuits/fault finding? How good are you at problem-solving?

Are you hoping for a S&T engineer here to just give you the answer?

 

[alxndr]

In one of your previous posts on here you've said you're going for a technician interview. I'm sorry but to be brutally honest, if you can't describe basic faulting techniques on a track circuit then you're not ready for a tech post yet.

 

[Annetts key]

Okay, looking at the OP other posts, he’s an operative and going for an interview for a technician job.

So to answer the original question. First thing is to do all the voltage tests. Then compare to the record card. This may give a clue. Foe example, if it’s fed off a cell or battery, has the cell/battery voltage dropped? If fed off the 110V supply, is that okay?

Is the feed-set / transmitter putting out enough power?

Next up, is this a short circuit fault or an high resistance fault? Again, comparing voltages to the record card helps. Is both the feed/transmitter and and the relay/receiver end voltages low? Or just the relay/receiver end?

As well as what type of track circuit equipment forms the track circuit, also important is the track (rails, fishplates (and hence bonds across the joints), IRJs, sleepers, any other metal items in the four foot, any point work / diamond crossings or level crossings).

Are any bonds off = high resistance connection?

Any cables damaged? Or poor connections? Both may cause high resistance faults.

Have any insulations failed or been bypassed (tie-bars fitted the “wrong way” round in point work)? Any IRJs that may be causing a problem? Or other insulations fitted to point operating equipment? All these are potential short circuits.

Also, depending on what technology and track circuit type it is, you may need different test equipment. Especially for audio frequency track circuits.

The overall aim is to gather information, then follow a logical step by step process to eliminate items that don’t fit the symptoms. And work your way through.

 

[rower40]

And check that there isn’t, in fact, a train in the section.

 

[Chris Hamilton]

And check that there isn’t, in fact, a train in the section.

Or, in one case for me, many years ago, a bogie left on the track by contractors.

We also regularly get reports of drivers, having pressed the button to lower the barriers at two of our stations, reporting to the signaller that the crossing sequence completed but the signal didn’t come off.

Yes driver, 2 aspect Signalling and a 5 mile section ahead of you. Have you considered that there may be a train present? I’m amazed that these reports make it past the signaller, the signalbox supervisor and control.

 

[66701GBRF]

Or, in one case for me, many years ago, a bogie left on the track by contractors.

We also regularly get reports of drivers, having pressed the button to lower the barriers at two of our stations, reporting to the signaller that the crossing sequence completed but the signal didn’t come off.

Yes driver, 2 aspect Signalling and a 5 mile section ahead of you. Have you considered that there may be a train present? I’m amazed that these reports make it past the signaller, the signalbox supervisor and control.

A driver is not necessarily to know the signal is red because there is still a train in section. No different to coming up to a red at any other place and SGing.

 

[Chris Hamilton]

No, but the signaller or signalbox supervisor should, and inform the driver of such. Not just phone control.